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Home My WebLink About03869 - Technical Information Report � �' 3�'r° � � `� . . . NW In c. Civil Enginee�ing � Su�veying TECHNICAL INF � RMATION REPORT FOR CHELAN CREEK PUD �_-------- ---------- ��------ -- ------___------------- e(� NovE�tBER 2015 0� � ti` � �� PREPARED FOR : JK MoNARCx LLC PO Box 188 PUYALLUP, WA 98371 visir�Tq� PREPARED BY: �P`' ut�va�y��, P,�c ( CARA VISINTAINER, P.E. y ' �� ,. APPROVED BY: ,� 4� �-.o �,�'� �i�• . '`-'��STt R� �t' CRAIG DEAVER, PRINCIPAL '�s�S•i��.�t F`�G , +�,'� � C.E.S . NW, INc. 310 29T'-' STREET NE, SUITE 101 nC�+Elv�� iCC PUYALLUP, WA 98372 (253) 848-4282 CITY OF RENTON PLANNING DIVISION / 38�c� .� . . . NW Inc. Civil Enginee�ing c� Su�veying TECHNICAL INFORMATION REPORT FOR CHELAN CREEK PUD NovEMBER 2015 PREPARED FOR: JK MoNARCH LLC PO Box 188 PUYALLUP, WA 98371 ` ,,p.VISINT,q� _p`F''�M�v,�s�� tt� PREPARED BY: � ,tsc. 'ti' 'S�_ � ;.'k¢ . . , O/ � CARA VISINTAINER, P.E. �, � APPROVED BY: `�.� ,� 42 1 a �,�'+� ��• . "�'�sTt:a� ��'' CRAIG DEAVER, PRINCIPAL ��S•S'/r��,��,F"��' tl'�+�1'1� C.E.S. NW, INc. 3 10 29T" STREET NE, SUITE 1 O1 PUYALLUP, WA 98372 �� ' (253) 848-4282 TABLE OF CONTENTS 1.0 PROJECT OVERVIEW Technical Information Report(TIR) Worksheet Vicinity Map Soils Map 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of the Eight Core Requirements 2.2 Analysis of Special Requirements 3.0 OFF-SITE ANALYSIS 3.1 Upstream Drainage 3.2 Downstream Drainage Course Sensitive Areas Map FEMA Map Downstream Map 4.0 ANALYSIS AND DESI N G ( 4.1 Existing Site Hydrology 4.2 Developed Site Hydrology 4.3 LID Feasibility 4.4 Flow Control Design 4.5 Water Quality Design Existing Conditions Map Developed Conditions Map Detention Facility Sizing Water Quality Facility Sizing � 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6.0 SPECIAL REPORTS AND STUDIES 7.0 OTHER PERMITS 8.0 ESC ANALYSIS AND DESIGN ' 9.0 BOND QUANTITY WORKSHEET 10.0 OPERATIONS AND MAINTENANCE � _ _ _ —� 1.0 PROJECT OVERVIEW The Chelan Creek PUD project consists of hvo existing parcels (APN #102305-9016, ]02305- 9440) on a 4.21-acre site located at 922 and 928 Chelan Avenue NE in the City of Renton, King County, Washington. The project also lies within the Southwest quarter of Section 10, Township 23 North, Range 5 East, W.M. Refer to the Vicinity Map within this section for a depiction of the project site. The site is irregular in shape and currently contains two existing single family residences. The remainder of the site is undeveloped and contains of a mix of forested areas and blackberry. The site is bound by single family residences to the north, Duvall Avenue NE on the east, the Hidden Creek Development to the south, and a church to the west. A Category 2 wetland and broad drainage swale bisects the site through the central portion within a well-defined Class 4 stream channel. Site soils consist of Alderwood gravelly sandy loam(AgC), also known as till soils. The site is moderately slopped with elevations ranging from approximately 438 feet along the northern boundary of the site to 410 feet at the southwestern boundary of the site. The Chelan Creek PUD will subdivide 4.21-acres into fourteen single-family residential lots, a Native Growth Protection Area (NGPA), open space, stormwater tract, public road, and private access tracts. The lots will be accessed directly from the internal roads and/or access drives to be designed in accordance �i�ith the City of Renton construction standards. The stormwater facilities are designed pursuant to the 2005 King County Surface Water Design Manual (KCSWDM) and the City of Renton Addendum. The stormwater standards require Level 2 Flow Control, Basic Water Quality, in addition to Flow Control BMPs. Stormwater runoff will be mitigated by an open stormwater pond located in the south��est portion of the site, Filterra Units, and basic dispersion of stormwater runoff from portions of the site. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner JK Monarch LLC Project Name Chelan Creek PUD Phone 253-840-5660 DDES Permit# Address PO Box 188 Location Township 23N Puyallup WA 98371 Range 5E Project Engineer Cara Visintainer, PE Section 10 Company CES NW, Inc. Site Address 922 Chelan Avenue NE Phone 253-848-4282 Renton, WA 98059 Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS 0 Landuse Services ❑ DFW HPA ❑ Shoreline Subdivison / Short Subd. / UPD ❑ COE 404 Management ❑ Building Services ❑ DOE Dam Safety � Structural M/F/Commerical / SFR RockeryNault/ X❑ Clearing and Grading ❑ FEMA Floodplain ❑ ESA Section 7 0 Right-of-Way Use � COE Wetlands ❑ Other ❑ Other ; Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) � Type of Drainage Review Full / Targeted / Type (circle one): Full / Modified / (circle): Large Site Small Site Date (include revision 6/15/15 Date (include revision dates): 14 5, 5 dates): Date of Final: Date of Final: � f Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental/ Blanket Description: (include conditions in TIR Section 2) Date of A roval: KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL ; TECHNICAL INFORMATION REPORT (TIR) WORKSHEET � Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Describe: - Start Date: , Completion Date: _ Part 8 SITE COMMUNITY AND DRAINAGE BASIN i Community Plan : Newcastle Special District Overlays: Drainage Basin: Lower Cedar River Stormwater Requirements: Level 2 Flow Control and Basic Water Quality ' Part 9 ONSITE AND ADJACENT SENSITIVE AREAS 0 River/Stream ❑ Steep Slope ❑ Lake ❑ Erosion Hazard Q Wetlands ❑ Landslide Hazard ❑ Closed Depression ❑ Coal Mine Hazard ❑ Floodplain ❑ Seismic Hazard ❑ Other ❑ Habitat Protection � Aquifer Protection Zone Part 10 SOILS Soil Type Slopes Erosion Potential AgC 8%-15% Moderate i ❑ High Groundwater Table (within 5 feet) ❑ Sole Source Aquifer ❑ Other ❑ Seeps/Springs ❑ Additional Sheets Attached I KING COUNTY. WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION /SITE CONSTRAINT ❑ Core 2 —Offsite Analvsis 0 Sensitive/Critical Areas Stream and Wetlands ❑ SEPA ❑ Other ❑ ❑ Additional Sheets Attached Part 12 TIR SUMMARY SHEET rovide one TIR Summa Sheet er Threshold Dischar e Area Threshold Discharge Area: name or descri tion Onsite Basin Core Requirements(all 8 apply) Dischar e at Natural Location Number of Natural Dischar e Locations: � Offsite Analysis Level: 1 / 2 / 3 dated: Flow Control Level: 1 / 2 / 3 or Exemption Number incl. facilit summar sheet Small Site BMPs Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor: TBD Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: riva / Public If Private, Maintenance Lo Re uired: Yes /No Financial Guarantees and Provided: es / No Liabilit Water Quality Type: Basic / Sens. Lake / Enhanced Basicm / Bog (include facility summary sheet) or Exemption o. Landsca e Mana ement Plan: Yes / No S ecial Re uirements(as a licable) Area Specific Drainage Type: CDA/ SDO/MDP/ BP/LMP/Shared Fac./ one Re uirements Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption / on 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: Source Control Describe landuse: (comm./industrial landuse) Describe any structural controls: KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Oil Control High-use Site: Yes /Qo Treatment BMP: Maintenance Agreement: Yes / No with whom? Other Draina e Structures Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS ; DURING CONSTRUCTION AFTER CONSTRUCTION - 0 Clearing Limits 0 Stabilize Exposed Surfaces , X❑ Cover Measures 0 Remove and Restore Temporary ESC Facilities 0 Perimeter Protection 0 Clean and Remove All Silt and Debris Ensure 0 Traffic Area Stabilization Operation of Permanent Facilities 0 Sediment Retention 0 Flag Limits of SAO and open space preservation areas X❑ Surface Water Control ❑ Other � Dust Control ' 0 Construction Se uence ; Part 14 STORMWATER FACILITY DESCRIPTIONS Note: Include Facilit Summa and Sketch Flow Control T e/Descri tion Water Qualit T e/Descri tion � 0 Detention Detention Pond ❑ Biofiltration - ❑ Infiltration 0 Wetpool Wetpond , ❑ Regional Facility 0 Media Filtration Filterra ❑ Shared Facility ❑ Oil Control ❑ Small Site BMPs ❑ Spill Control 0 Other Basic Dispersion ❑ Small Site BMPs ❑ Other , I � I � KING CUUNTY, WASIIING'I'ON, SUl�1�AC1; WA7'L-'R DI?SIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS 0 Drainage Easement ❑ Cast in Place Vault ❑ Access Easement ❑ Retaining Wall � Native Growth Protection Covenant 0 Rockery > 4' High 0 Tract ❑ Structural on Steep Slope ❑ Other ❑ Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervisi�n, have visited the site. 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'. _ `4 . �s , '* � d ..�^�. � �...1. :l�l �.! r 1 „+� �. ;,_ "+? _ —__�. � � M _k +a ,C " � —� '.�"- � � ,��i_ �*� �`"-;' �-_l +1_� Notes � Legend None City and County Boundary o�r�er �� City of Renton l., O 1 st Floor 1st Floor 2nd Floor 1st Floor 5�2 0 256 512 Feet Other Buildings WGS_1984_Web_Mercator_Auxiliary_Sphere Buildings Information Technology-GIS r�s�,a�- 3�� : F d�:� �ai c o-.:��i � , i� ei m�pF�,g_ie�na �'1}�Of �s f�,i -f _i_e�n i D .; �.� _Ih.,� �N� ar o tF 5 n ap� q o m y no�be `7 _ � On ;-' RentonMapSupport(c�Renronwa.gov acc�ra e c r ai� o�ha�,+ise ie ab�e Finance&IT Division 6/13l2015 THIS MAP IS NOT TO BE USED FOR NAVIGATION � � r � � � � 3 Soil Map—King County Area.Washington 3 � � � � � � 563380 r. .- ,—._.- ..-.-� -. —.-�� c..:-.-. .-� a7°29'S5 N 2 � . � 47°29'S5'N c �� °wif L` ��' . , �'��i ;.�i+�'�1' � � . . z �`4..� �:, .��a:"�_ .=f ..t. �y, .i�, i II �� o ` � �� .f�� _ �.+ �n Y� . ,i�<. � �... �; . � , �� f .�� £ �R � f . a(' ,z+`;�'. � � sM,�' .,:,. .4... �s � � � �-. 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Area of Interest(AOq i �'y Stony Spot Soils Warning:Soil Map may not be valid at this scale. f� Very Stony Spot Enlar ement of ma s be ond the scale of ma in can cause Soil Map Unit Polygons 9 P Y PP 9 �� Wet Spot misunderstanding of the detail of mapping and accuracy of soil line ...� Soil Map Unit Lines placement.The maps do not show the small areas of contrasting _� Other soils that could have been shown at a more detailed scale. � Soil Map Unit Points _ +� Special Line Features Special Point Peatures Please rely on the bar scale on each map sheet for map V Blowout �Nater Features measurements. Streams and Canals (� eorrow Pit Source of Map: Natural Resources Conservation Service Transportation Web Soil Survey URL: http://websoilsurvey.nres.usda.gov � Clay Spot � Rails Coordinate System: Web Mercator(EPSG:3857) ,;• Closed Depression +,r, Interstate Highways Maps from the Web Soil Survey are based on the Web Mercator � Gravel Pit US Routes projection,which preserves direction and shape but distorts distance and area.A projection that preserves area,such as the „ Graveuy Spot Major Roads Albers equal-area conic projection,should be used if more accurate � Landfill Locat Roads calculations of distance or area are required. � Lava Flow eackground This product is generated from the USDA-NRCS certified data as of the version date(s)listed below. � Marsh or swamp � Aerial Photography Soil Survey Area: King County Area,Washington � Mine or Quarry Survey Area Data: Version 10,Sep 30,2014 I � Miscellaneous water Soil map units are labeled(as space allows)for map scales 1:50,000 � Perennial Water of largef. -:,� Rock Outcrop Date(s)aerial images were photographed: Jul 8,2014—Jul 15, ..�. Saline Spot 2014 The orthophoto or other base map on which the soil lines were . e Sandy Spot compiled and digitized probably differs from the background � Severely Eroded Spot imagery displayed on these maps.As a result,some minor shifting of map unit boundaries may be evident. t,� Sinkhole �� Slide or Slip � Sodic Spot u� Natural Resources Web Soil Survey 6/13/2015 Conservation Service National Cooperative Soil Survey Page 2 of 3 Soil Map—King County Area,Washington i ' Map Unit Legend King County Area,Washington(WA633) �I_ _ Map Unit Symboi Map Unit Name Acres in AOI Percent of AOI AgC Alderwood gravelly sandy loam, 4.0 100.0% , 8 to 15 percent slopes Totals for Area of Interest 4.0 100.0% �- �. ; , i i � � usu,� Natural Resources Web Soil Survey 6/13/2015 � Conservation Service National Cooperative Soil Survey Page 3 of 3 2.0 CO\DITIONS A1�D REQL'IREMENTS SU1�I�IARY The project is subject to Full Drainage Review as dictated by the 2005 King County, Washington Surface Water Design Manual (KCWSWDM) Core Requirements No. 1 through 8 and Special Requirements No. 1 through �. 2.1 Analysis of the Eight Core Requirements C'ore Requirement No. 1: Discharge at the 1Vatural Location. The intent of this requirement is to "prevent adverse impacts to doia�nstream pr-operties caused by diversion of flow from one flowpath to anothef-, and to discharge in a manner that does not significantly impact downhill properties or-drainage systems, " KC W S W DM page 1-21. Response: The developable portions of the site will drain to the southwest across the wetland buffer into the existing onsite stream. After development, runoff will discharge at the edge of the buffer through rock outfall structures. The drainage course for the site will remain unchanged. Core Requirement No. 2: OfJ=Site Analysis. The intent of this requirement is to identify and evaluate off-site flooding and erosion problems that may be created or aggravated by the proposed project and to ensure appropriate measures are provided for preventing creation or aggravation of those problems. Response: 'This project is proposing to detain runoff and release at pre-developed rates and durations based on a forested cover condition. This is going to result in lower peak flows from the site; therefore, no off-site flooding or erosion problems will be created or aggravated by this project. In addition, the Levei One Do�vnstream Analysis is located within Section 3.0 of this report. Core Requirement No. 3: Florv Conh-ol. , The intent is to ensure the minimum level of control needed to protect downstream properties and resources from increases in peak, duration, and volume of runoff generated by new development. Response: This site is mapped within in a Level 2 Flow Control zone according to the City of Renton flow control map. Please refer to Section 4.0 flow control calculations. ('r�re Rc°c/irirc iu��t .A'r�. -l: Co��r�i'urtrc� .Sl•stenr. I�he intent of this requirement is to ensure proper design and construction of engineered conveyance system elements. Response: Pipe Systems: The proposed conveyance system is comprised of a storm drainage pipes and catch basins. The conveyance system is sized to convey the 100-year developed peak flo«� and analyzed using the Rational Method in Section 5.0. Culverts: There are no proposed culverts for this development. Drtches/Channels: There are no proposed ditches for this development. C'��re Rer yuirernent No. J: Temporary Erosion and Sediment Control. rhe intent of this requirement is to prevent the transport of sediment and other impacts, such as increased runoff,related to land disturbing activities. Response: A Temporary Erosion and Sedimentation Control (TESC) Plan has been prepared as part of the Construction Plans. The TESC Plan will prevent the transport of sediment to streams, ��etlands, lakes, drainage systems, and adjacent properties in accordance with all the applicable standards of the KCWSWDM and the City of Renton. C'ore Requir�ement No. 6: Maintenance and Operations. The intent is to ensure that the maintenance responsibility for drainage facilities is clearly assigned and that these facilities will be properly maintained and operated in perpetuity. Response: The onsite stormwater components will be located within public and private right of ways. See Section 10.0 for maintenance standards for the privately maintained drainage components. C'or�e Rc yirir-ement,'�'o. 7: Financial Guurantees and Liabili��. This requirement is intended to ensure financial guarantees are posted to sufficiently cover the cost of correctin�, if necessarv. incomplete or substandard drainage facilit�� construetion ��ork, and to warrant for two years the satisfactory performance and maintenance of those newly- �I constructed drainage facilities to be assumed by the Cit�� of Renton for maintenance and I operation. Response: Bond Quantities are included in Section 9.0. �I Core Requirement No. 8: Water Qualih°. The intent of the water quality requirement is "to requir�e an efficient, cost-ef�ective level of water quality treatrnent tailored to the sensitivities and resource protection needs of the downstream II receiving water to x�hich the project site drains." , "Core Requirement No. 8 requires that water quality treatment facilities be provided to remove poll utants from runo�discharging from the project site." Response: A Stormwater Wetpond and/or Filterra Units will provide Basic Water Quality treatment for the pollution generating impervious surfaces. � 2.2 Analysis of Special Requirements ' Special Requirement No. 1: Other Adopted Area-Specific Requirements. � Response: The following is a list of other possible adopted area-specific requirements according to the KCWSWDM: Critical Drainage Areas—This development is not located �i�ithin a critical drainage area. Master Draina e�Plan—The area is not part of a master drainage plan. Basin Plans — This site is located within the Lower Cedar River drainage basin. No additional requirements have been identified. Salmon Conservation Plan — The site is located within the WRIA 8 Chinook Salmon Conservation Plan Area. No additional requirements apply. Lake Management Plan — It does not appear that there is a Lake Management Plan that impacts the proposed development. Shared Facility Draina�e� — The project does not propose to connect to a shared detention facility system or create a shared facility. This plan does not apply. � Sp�cicrl Reytrir��n��fu .A'u. '.� f-7nn�1 H��_�n•�l.��r•��u D�lir��rlin��. Response: The proposed sitc is not (ocated �a ithin the 100-year floodplain or flood hazard area. See included FE��1A map within Section 3.0 of this report. Speciul R�cjirir�»r�nt:'�'r�. 3: Flc�ud Prr�te�•tir�r7 Fucilitic�.r. Response: Spe�ial Requirement No. 3 is not applicable to the proposed site since the �ite �ti�ill not affect any existing flood protection facilities. Special Requirement 1Vo. 4: Source Control. Response: Special Requirement No. 4 onl� applies to commercial site de�elopment permits. Since this site is single family residential, this requirement does not appl�. Special Reyr-�ir•cn�erzt.�'o. �: Orl Coi�tr�ol. Response: Special Requirement No. � does not appl} to the site since it is not classified as a high-use site. Special Re��uir�e�r�ent.�'o. 6: .Aqi�ifer Protcctiofz Ar�ea Response: A small area within the southeastern portion of the site is located within the City of Renton's Aquifer Protection Zone 2. Since no open flow control, water quality facilities, ditches, or channels are proposed, no additional requirements apply. 3.0 OFF-SITE ANALYSIS 3.1 Upstream Drainage Upstream stormwater enters the site along the eastern boundary through an existing 24-inch culvert beneath Duvall Avenue NE. There is no identified lack of capacity within the existing 24- inch culvert. The upstream basin is approximately 50 percent developed with residential property. Storm��ater from the upstream combines with onsite stormwater runoff and flows within the onsite drainage channel to the southwest for approYimately 625-feet until leaving the site. The upstream flow does not enter the disturbed or developed portion of the site and will not impact the proposed development. 3.2 Downstream Drainage Course The existing site is relatively flat with an open drainage channel flowing from the northeast corner to the southwest corner of the site. The drainage channel is heavily vegetated with trees, blackberries, and understory. After leaving the site, the drainge channel flows 370-feet to the south and enters an existing 18-inch storm drainage conveyance line �vithin NE 8"' Street. Runoff then generally flows southerly through a series of public and private storm drainage pipes and ponds until discharging into Maplewood Creek approximately one mile downstream of the site. There were no problems identified or observed during our site reconnaissance. In addition, there was no evidence of a lack of capacity or erosion/sedimentation downstream of the site. 3.3 Resource Review • Adopted Basin Plans: The site is part of the Lower Cedar River drainage basin. • Finalized Drainage Studies: This is not applicable. • Drainage Area Maps: Per the City of Renton Flow Control Map, the site is subject to Leve12 Flow Control. • Floodplain and Floodway FEMA Maps: The FEMA map for this area shows that the site is located in Zone X and is not subject to flooding. Please see the FEMA map within this section. • Sensidve Areas Folios: Based on a review of the Renton and King County Sensitive Areas Maps, it was found that the subject site does not contain any seismic hazards, coal mines, landslide hazards, or erosion hazards. However, the onsite stream and wetland have been delineated bv Altmann Oliver Associates. • Road Drainage Problems: This is not applicable. • United States Department of Agriculture King County Soils Surr•ey: Based on the soils map for this area, the entire site is located within Alderwood-type soils. Alderwood soils are classified as gravelly sandy loam to a depth of 12 inches and gravelly, sand loam with organics beriveen 12 and 27 inches. This gravelly, sand loam layer is underlain by consolidated till to a depth of 60 inches. Permeability is moderate in the surface layers ad very slo�v in the till layer, runoff is slow to medium, with moderate erosion potential. • Migrating River Studies: This is not applicable. � ` 1 '. I ti � ; I � � I � � i J ;-� I � rn � n � n -o IlL�1N.11l 122°09'22., _ __ ___._...___. __ -- -.. -.---- -- - --_____ _- 47�30'00" APPROXIMATE SCALE IN FEET __ _.__ .__. _._.____._ _ � I �' 500 0 500 Z } I O � �I ~ Z Z � �� I � � I � NATIONAL FLOOD INSURANCE PRUGRAM F-- Y I �1llllfIDl�� . —_—_- -- -- —__� U � I I FIRM coRPORarE uMiTs FLOOD INSURANCE RATE MAP KfNG COUN'CY SITE vxrNcoeroka�r�i� �x�,�s KING COUNTY, uu�� WASHINGTON AND INCQRPOR.ATED AREAS PANEL 9810F 1125 ISLt. nnnr in�ULx i�pH �°nNLLS NG7 PRiNTED) iONTaiNS COn4MUNRY NUMOER PANEL SUfFIX muNn. ��JninCJF70RnTED aAEaS ;�W�i O9ai F errvioa.cuv r_�r aooea oaFn F 10 MAP NUMBER 53033C0981F ��,��,� MAP REVISED: 4�°-°°�� MAY 16,1995 �, I�� ,�'� o� . � .,,, Federal Emergency Management Agency This is an otFcial copy of a portion of the above referenced flood map. It was extracted using F-MITOn-Line. This map does not rellect changes or amendments which may haee been made subsequent to the datc on thc title block. For the latest product information about National Flood Insurance Program flood maps check thc FEMA Flood Map Store at wwW.msc.fema.gov I I � rn z � � G rn n �o rn n � � n � i Sensitive Area Map � �� - - -- � :,� � — . ��: �.. � ` � � = '� ,� '_ .,� -. �� `��- . ��e.. � .. . 's�S` K , � f ,. ! `z ..;� ' ,. ' .yt.: � ?� �M � ' �, :�- .,i . N . ' ' .�. . S� 2 �.: �� . ' ..�_ . y� t ` � � � . ' ;.� �. �Ya �. .:� � '�, �'. - i: `1 �'�F�,� ,. , � _ - � f � '"�' J�. 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Qsd 953 y 950 953 ,,�.,.�.,,.,.:�` �:1 y CI_ � 95•� �io� ^ 928 Q 420'1 919 4218 920 9�q � 918 921 �. 431 8 �° d 5'I 9 � � �y �=� 91 5 9 1 3 4336 9 1 4 a' 9 2 2 `�' �, 9 1 3 � gt2 4225 `- �1L �, 947 4340 �,�.�,.�.�,,,��.�,� », .t,>, � .,,�.„908 �,^„�.� ;, gp2 g07 � 906 999 4311 4331 �345� � �v� .*,4217 �2 4822� 49a4 903 a2os ,;�' SITE � st t '� � ��,�:. ...�.�,... _.� �.. . �� 451 88T 8$6 860 8fi4 _.4863 '` 4g05 4911 861 $73 880 �_ 850 867 87� 858 857 ': 8� 863 855 862868 ? 8� � 854 859 � 856 '� 8 51 � 850 821 848 855 82 3 82 6 82 5 824 0 , 81 5 812 C N N�ney Dr'�ti, �,, 819 � 818 � 817 nneydew Athletrc FrelOs �' � ntary Schoof 816 813 'i 812 � $09 '� 806 �26 813 � 816 $08 807 ^ 806 � _ 807 '�, 8Q2 ,� �5� 801 800 803 : 8� 4820 801 `"�►v�.�.�„�st � ,-, ,,�;. �;_,:� . _ ..,p.�.�., .�_�:�.,.�.��...,� 4209 �7644225 �� a7� 753 NE 755 769 �3� '�18 �i418 ;, 4512 4530 4548 4716 75� ��5 �760 758 � a['i08 T�9 752 �� 767 � 745 ��-_ �,�,�a:�� : . � �� . ,�A., M .,.� 761 - 7G1 763 752 75-3 �300 ��^^°� � � 4614 z - � ��9 � = T59 752 �5603 .�620 �701 � 4810 4816 � � Q. 47U7 755 -- 14008 755 749 748 4307 ,�r�. 755 748 4609 - � �. � �'' � 4631 � i�„1 +�}� � 42 04 �� .3322 a� 751 � 742 �615 ^- ; 1211 5 72 6 4210., 4416 E � �747 '� 736 T ' 48�13 733 � 14005 491 5 �' \ 723 , ,��4217:_ �i3 04 �..,� � ` t 741 � 72 4 718 712 =, T2 7 _ .,h, 706 ,� 4211 �43i�5 � 4323 671 � � 737 °'� rt7 70$ 4916 4205 'X, ��11 �� 733 ��E 700 ¢. � � . 66 5 � � *� `� "-" 72 9 ,w..��314 657 715 707 - - 412d 682 � 4406 �3 �,� �a � I- y 651 - - _, , � 4302 � __ .__ ! ,_. 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Q"., ,.: , � . v� .� _ It� � M 9� r:r �E 6th St - � _ �_ .�,,�,..,. . u., ,� � � . - - - " �.� �, 4310 �i316 565 555 :,y� 581 q516� 587 M, '+ '. 5013 5025� 5�'� - . 575 4608 4626 � � 5$3 `18�� 834 579 � 576 575 5001 _. ` ` �t _. �,�5-,. �,' Ij 573 ':c7 570 569 565 555 . 4322 t �9 �� 568 li, - " 580 � 562 a3 565 �1 575 �17 567 °1 5&l 553 5� 4319 = _ �� 5� LL� 4605 561 �2 Q 571 �_ 570 � 559 � 557 � f 556 � 565 566 559 '�� 558 557� �;v ��1� 557 562 555 ,_ �i325 c 551 n 4606 553 � 550 F' S51 5552 5S2 551 Z, 5014 r� � 4310 _ y 4 � �, _• l�n 52 3 ' �� 553 ��.� 530 520 '� 519 � t� � 525 �r' 526 �!'K 521 'r,�-.^_ 513 a' 451 5 4611 523 524 �,l n 517 g�q 51 5 "_��..... �.�.-.�. � ' 5003 5021 >. �..� _ � 507 � �517 518 «} . 511 508 509 4 5 01 452 0 4612 >� 511 � 5.�� , 511 ... 512 5a5 _ 5U2 � d311 431 5 �505 � ; �' 4818 , � ''_ 503 5012 519 � - ,,�,� 506 ; ,� - �� _ , � J, _�; ..,.,, : (�.... _, � ,,,,,.,,,..,L+}.,��+ : �_T� �806 507 : 4507 4603 462'I 500 4800 4815 4833 L 4915 5005 5017 :. _ _ � V . 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I . , � _ 0 . . �.�tt`�lhrrrL:..� l�.�� . _ �� - � :. . .. -- - - . ;. , . , � _ : . ,,. � Information Technology - GIS This map is a user generated static output from an Internet mappi�g site and �s for reference only Data layers that appear on this map may or may not be Clly Of �� I512 0 256 512 Feet RentonMapSupport@Rentonwa.gov accurate, current, or otherwise reliable. WGS_1984_Web_Mercator_Auxiliary_Sphere 06/15/2015 THIS MAP IS NOT TO BE USED FOR NAVIGATION Finance &IT Division -t.0 STORMWATER A:vALYSIS AND DESIGN 4.1 Existing Site Hydrology The site is irregular in shape and currently contains two existing single family residences. The remainder of the site is undeveloped and consists of a miY of forested areas and blackberry. The site is relatively flat and slopes to the central portion into an existing stream, wetland, and associated buffer. On-site soils are Alderwood Gravelly Sandy Loam (AgC), classified as till soil. Please refer to the Pre-Developed Basin Map for the etisting site conditions. Since this site requires Level 2 Flo�� Control, a forested till land cover was assumed for target surfaces in the existing condition for modeling purposes. The pre-developed peak flows far the site (4.21-acre)are as follo�;�s (from KCRTS output): Q�=0.117 cfs Qio= 0.204 cfs Qzs=0.265 cfs Q�oo= 0.340 cfs 4.2 Developed Site Hydrology Limits of site disturbance ��-i11 include installation of sediment and erosion control Best Management Practices (BMPs), construction of a public road, private access road, utilities, stormwater BMPs and facilities, �i�etland buffer enhancement, and grading the single family residential lots. Frontage improvements include curb, gutter, and side«�alk addition on the western side of Duvall Avenue NE. The total disturbed area �i=ill cover approximately 2.30 acres of the esisting 4.21 acre site. Upon completion of the project, impervious surfaces covering the site include approximately 0.36-acre of asphalt roadway, 0.13-acre of concrete driveways,and 0.84-acre of new rooftops. Roof areas were determined by applying a restricted impervious surface BMP footprint. Further, calculations account for 65% of the lot as impervious roof area instead of the maximum 75% as � allowed by code. The remainder of the site will include residential lawn and an open space/sensitive areas tract. To meet the City of Renton's stormwater requirements (Level 2 Flow Control, LID BMPs, and Basic Water Quality), the project will construct an open combined detention and water quality pond, provide Contech Filterra Units, and utilize basic dispersion of roof areas. In the developed condition, an onsite bvpass basin of 0.48-acres �i ill include storm�vater from Lots 1 through 4 and ne�i� impervious from Tract C. The roof areas from Lots 1 through 4 will utilize basic dispersion and will discharge directly to the ��-etland buffer. The impervious within Tract C in addition to runoff from the residential driveways ��ill be treated in a Filterra Unit and then discharge to the wetland buffer. The developed peak flows for the bypass basin are as follows(from KCRTS output): Q�=0.067 cfs Q�o= 0.080 cfs Q�;=0.089 cfs Q,00=0.154 cfs Runoff from the remaining portion of the site will be over-detained to compensate for unmitigated flows �;-ithin the bypass basin. The 3.73-acre onsite developed basin will also utilize basic dispersion for roof runoff. Flow performance standards were analyzed at the downstream point of compliance, �vhere detained and undetained project flows are combined. The developed peak flows for the onsite basin are as follows(from KCRTS output): Q�=0.283 cfs Qio=0396 cfs Q�s=0.434 cfs Q,00=0.746 cfs A portion of storm«-ater from Duvall Avenue the frontage improvement area will be discharged to the wetland buffer after being treated in Filterra Units. Please refer to the Developed Basin Map for the proposed improvements. 4.3 LID Feasibilih' Based on Figure C.1.3.A of Appendix C in the KCSWDM, both full dispersion and full infiltration are not feasible based on inadequate vegetated flow path lengths and site soils. Basic dispersion on all residential lots is utilized for the site since 50-foot vegetated flow path segments are available. Each roof area will be discharged onto a rock pad and/or splash block �vith a 50- foot minimum vegetated flow path. These areas are assumed to be 50% grass / 50% impervious for the purposes of detention s��stem modeling. 4.4 Detention Facility Sizing The detention pond was sized using The King County Runoff Time Series (KCRTS) methodology «�as used to meet the volume outflow design requirements for Level 2 Flow Control. The pond ��-i11 release runoff to match the predeveloped flows and durations for SO percent of the 2-year up to the 50-year storm events. The pond��ill detain approximately 24,642 cubic feet of storm«-ater with a live storage depth of 6 feet. Please refer to the KCRTS calculations within this section. � 4.5 Water Quality A ��ater quality ��etpond will treat stormwater from a majority of the developed portion of the site. The water quality ��etpond will be placed beneath the detention pond as dead storage. The required volume of the wetpond is 1,985 cubic feet. Wetpond sizing is included within this section. Within the bypass basin, a Filterra Unit is proposed to treat runoff from pollution generating impervious surfaces from the access road prior releasing runoff into the wetland buffer. ln addition, two Filterra Units are proposed to treat stormwater from the frontage area. 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Time Series Computed i KCRTS Command CREATE a new Time Series Production of Runoff Time Series Project Location : Sea-Tac Computing Series : chelanbypass.tsf Regional Scale Factor : 1. 00 Data Type : Reduced Creating Hourly Time Series File Loading Time Series File:C: \KC SWDM\KC DATA\STTG60R.rnf . Till Grass 0.28 acres Loading Time Series File:C: \KC SWDM\KC DATA\STEI60R.rnf . Impervious 0.20 acres -------------- Tota1 Area : 0 . 48 acres Peak Discharge: 0. 154 CFS at 6: 00 on Jan 9 in Year 8 Storing Time Series File:chelanbypass.tsf . Time Series Computed � �, I, ------------- i CREATE a new Time Series I ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : chelandev.tsf Regional Scale Factor : 1 . 00 Data Type : Reduced I Creating Hourly Time Series File Loading Time Series File:C: \KC SWDM\KC DATA\STTF60R.rnf . Till Forest 1. 91 acres Loading Time Series File:C: \KC SWDM\KC DATA\STTG60R.rnf . Till Grass 0. 96 acres Loading Time Series File:C: \KC SWDM\KC DATA\STEI60R.rnf . Impervious 0. 86 acres -------------- Tota1 Area : 3. 73 acres � Peak Discharge: 0. 746 CFS at 6: 00 on Jan 9 in Year 8 Storing Time Series File:chelandev.tsf . Time Series Computed � ' chelanpre.pks Flow Frequency Analysis Time series File:chelanpre.tsf Project Location:5ea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (�FS) (CFS) Period 0.265 2 2/09/Ol 18:00 0. 340 1 100.00 0.990 0.072 7 1/06/02 3:00 0.265 2 25.00 0.960 0.197 4 2/28/03 3:00 0.204 3 10.00 0.900 0.007 8 3/24/04 20:00 0.197 4 5.00 0.800 0. 117 6 1/05/05 8:00 0.172 5 3.00 0.667 0.204 3 1/18/06 Z1:00 0.117 6 2.00 0. 500 0.172 5 11/24/06 4:00 0.072 7 1.30 0.�31 0. 340 1 1/09/08 9:00 0.007 8 1.10 0.091 Computed Peaks 0.315 50.00 0.980 I � I ' � I ; , � f � Page 1 � chelanbypass.pks Flow Frequency Analysis , Time Series File:chelanbypass.tsf Project Location:5ea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate rtank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.074 5 2/09/O1 2:00 0.154 1 100.00 0.990 0.056 7 1/05/02 16:00 0.089 2 25.00 0.960 0.089 2 2/27/03 7:00 0.080 3 10.00 0.900 0.055 8 8/26/04 2:00 0.078 4 5.00 0.800 ' 0.067 6 10/28/04 16:00 0.074 5 3.00 0.667 0.078 4 1/18/06 16:00 0.067 6 2.00 0. 500 0.080 3 10/26/06 0:00 0.056 7 1.30 0.231 0.154 1 1/09/08 6:00 0.055 8 1.10 0.091 Computed Peaks 0. 132 50.00 0.980 Page 1 chelandev.pks Flow Frequency Analysis Time series File:chelandev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0. 370 4 2/09/O1 2:00 0.746 1 100.00 0.990 0.259 7 1/OS/02 16:00 0.434 2 25.00 0.960 0.434 2 2/27/03 7:00 0.396 3 10.00 0.900 0.232 8 8/26/04 2:00 0.370 4 5.00 0.800 0.283 6 10/28/04 16:00 0. 364 5 3.00 0.667 0.396 3 1/18/06 16:00 0.283 6 2.00 0. 500 0. 364 5 11/24/06 3:00 0.259 7 1.30 0.231 0.746 1 1/09/08 6:00 0.232 8 1.10 0.091 Computed Peaks 0.642 50.00 0.980 Page 1 Retention/Detention Faciiity Type of Facility: Detention Pond Side Slope: 3. 00 H: 1V Pond Bottom Length: 86. 00 ft Pond Bottom Width: 18 . 00 ft Pond Bottom Area: 1548 . sq. ft Top Area at 1 ft. FB: 7680 . sq. ft 0. 176 acres Effective Storage Depth: 6. 00 ft Stage 0 Elevation: 415. 00 ft Storage Volume: 23112 . cu. ft 0. 531 ac-ft , Riser Head: 6. 00 ft Riser Diameter: 12 . 00 inches Number of orifices: 2 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0. 00 0 . 90 0. 059 2 4 .00 2 .00 0.153 4. 0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs} (sq. ft) 0 .00 415. 00 0. 0.000 0. 000 0 . 00 1548 . ' 0. 01 415. 01 16. 0 . 000 0.002 0.00 1554. 0. 02 415. 02 31. 0. 001 0. 003 0. 00 1560. 0. 03 415. 03 47. 0.001 0. 004 0 . 00 1567. 0. 04 415. 04 62. 0 . 001 0.004 0.00 1573. 0.05 415. 05 78. 0. 002 0.005 0.00 1579. 0.06 415. 06 94. 0. 002 0.005 0 . 00 1586. 0. 07 415. 07 110. 0. 003 0.006 0.00 1592 . 0. 18 415. 18 289. 0. 007 0.009 0.00 1661. 0.28 415 . 28 458 . 0.011 0.012 0 .00 1726. 0 . 38 415.38 639 . 0. 015 0. 013 0. 00 1790. 0 . 4� 415. 48 816. 0 . 019 0. 015 O. GO 1856. 0.58 415. 58 1005. 0. 023 0 . 017 0 . 00 1922 . 0. 68 415. 68 1201. 0. 028 0.018 0. 00 1989. 0.78 415.78 1403. 0. 032 0.019 0. 00 2057. 0 . 88 415. 88 1612. 0 . 037 0.021 0. 00 2125. 0. 98 415. 98 1828. 0. 042 0. 022 0 . 00 2194. 1. 08 416. 08 2051. 0. 047 0. 023 0. 00 2264. 1 . 18 416. 18 2281. 0. 052 0.024 0. 00 , 2334 . 1 .28 416.28 2518 . 0 . 058 0. 025 0 . 00 2406. 1 .38 416. 38 2762 . 0 . 063 0 . 026 0 . 00 24�8 . 1 . 48 416. 48 3013. 0. 069 0.027 0.00 2550 . 1 .58 416.58 3272 . 0. 075 0. 028 0.00 2624 . 1 . 68 416. 68 3538. 0.081 0.028 0. 00 2698 . 1.78 416.78 3812. 0.088 0. 029 0. 00 27�3. 1. 88 416. 88 4093. 0.094 0.030 0. 00 2848 . ' 1. 98 416. 98 4381. 0 . 101 0. 031 0.00 2925. 2 .08 417 .08 4678 . 0.107 0.032 0.00 3002 . 2 . 18 417. 18 4982. 0.114 0. 032 0. 00 3079. 2 .28 417 .28 5294. 0. 122 0. 033 0.00 3158 . 2 . 38 417 .38 5613 . 0. 129 0. 034 0.00 3237 . 2 .47 417 .47 5908 . 0.136 0.035 0. 00 3309. 2 .57 417.57 6243. 0. 143 0. 035 0. 00 3389. 2 . 67 417 . 67 6586. 0.151 0.036 0. 00 3471. 2 .77 417 . 77 6937. 0.159 0.037 0. 00 3553 . 2 .87 417 . 87 7296. 0 . 168 0 . 037 0. 00 3635. 2 . 97 417. 97 7664. 0.176 0.038 0.00 3719. 3 . 07 418. 07 8040. 0. 185 0.039 0 . 00 3803 . 3 . 17 418. 17 8425. 0.193 0.039 0 . 00 3888 . 3 .27 418.27 8818 . 0.202 0. 040 0. 00 3973. 3.37 418 . 37 9219. 0.212 0.040 0.00 4060. 3.47 418. 47 9630. 0.221 0. 041 0. 00 4147 . 3.57 418.57 10049. 0 .231 0. 042 0 . 00 4234 . 3 . 67 418. 67 10477 . 0.241 0. 042 0. 00 4323. 3 .77 418 .77 10913 . 0.251 0.043 0.00 4412 . 3. 87 418 . 87 11359. 0.261 0. 043 0. 00 , 4502 . 3. 97 418. 97 11814. 0 .271 0. 044 0.00 4593. 4 . 00 419.00 11952 . 0.274 0. 044 0.00 4620. 4 . 02 419. 02 12045. 0 .277 0. 045 0. 00 4638 . 4 . 04 419. 04 12138 . 0.279 0. 047 0 . 00 4657 . 4 . 06 419. 06 12231 . 0.281 0. 052 0.00 4675. 4 .08 419. 08 12325. 0.283 0. 058 0.00 4693. 4 . 10 419. 10 12419. 0.285 0. 065 0. 00 4712 . 4. 13 419. 13 12560. 0 .288 0.074 0.00 4739. 4. 15 419. 15 12655. 0.291 0.083 0.00 4758 . 4 . 17 419. 17 12751. 0.293 0.089 0.00 4776. 4 .27 419.27 13233. 0 .304 0. 101 0.00 4869. 4 .37 419.37 13724 . 0.315 0.112 0.00 4962 . 4 .47 419. 47 14225. 0.327 0. 121 0.00 5057 . 4 .57 419.57 14736. 0.338 0. 129 0.00 5152 . 4 . 67 419. 67 15256. 0.350 0.136 0. 00 5297 . 4 .77 419.77 15785. 0.362 0. 143 0.00 5344 . 4 . 87 419. 87 16324. 0.375 0. 149 0. 00 5441. 4 . 97 419. 97 16873. 0 .387 0. 156 0 . 00 5539. 5 . 07 420. 07 17432. 0. 400 0. 162 0. 00 5'c37 . 5 . 17 420. 17 18001. 0. 413 0. 167 0. 00 5736. 5 .27 420.27 18579. 0.427 0. 173 0.00 5836. 5.37 420. 37 19168 . 0.440 0. 178 0.00 5937 . 5.47 420. 47 19767. 0. 454 0. 183 0 . 00 6038 . 5.57 420. 57 20376. 0.468 0. 188 0 . 00 6141. 5 . 67 420. 67 20995. 0.482 0. 192 0. 00 6293 . 5 . 77 420. 77 21625. 0. 496 0. 197 0.00 6347 . 5. 87 420. 87 22264. 0 . 511 0.201 0. 00 , 6451. 5. 97 420. 97 22915. 0.526 0.206 0 .00 6556. 6. 00 421. 00 23112. 0.531 0.207 0.00 6588. 6. 10 421. 10 23776. 0.546 0. 519 0.00 6694. 6.20 421.20 24451. 0 . 561 1. 090 0. 00 6801 . 6.30 421.30 25136. 0.577 1.820 0. 00 6908 . 6. 40 421. 40 25832. 0.593 2 . 620 0. 00 7016. 6.50 421.50 26540. 0. 609 2 . 900 0.00 � 7125. � 6. 60 421. 60 27257 . 0 . 626 3. 160 0.00 7235 . 6.70 421.70 27986. 0.642 3. 400 0.00 7345. 6. 80 421. 80 28726. 0.659 3. 620 0.00 7456. 6. 90 421. 90 29478 . 0 . 677 3.830 0.00 7568 . 7 .00 422.00 30240. 0. 694 4.030 0. 00 7680. 7 . 10 422. 10 31019. 0.712 4.220 0 . 00 7793. 7 .20 422 .20 31799. 0.730 4 . 400 0.00 7907 . 7 .30 422 .30 32595. 0.748 4.570 0.00 8022 . 7 . 40 422. 40 33403. 0.767 4.730 0 . 00 8137 . 7 .50 422 .50 34223. 0 .786 4. 900 0. 00 8253. 7 .60 422 . 60 35054. 0.805 5. 050 0. 00 8370 . 7 .70 922.70 35896. 0.824 5 .200 0. 00 8987 . 7 . 80 422 . 80 36751. 0. 844 5 . 350 0 . 00 8505. 7 . 90 422 . 90 37618 . 0. 864 5. 490 0.00 �724. Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 0.75 0.21 6. 00 421. 00 23116. 0.531 2 0.37 0. 19 5. 62 420. 62 20671. 0.475 3 0. 43 0. 15 4 . 82 419. 82 16075. 0.369 4 0.36 0. 13 4 . 65 419. 65 15134. 0.347 5 0.40 0. 13 4 .55 419. 55 14616. 0. 336 6 0 .23 0. 08 4 . 15 419. 15 12661 . 0 .291 7 0.26 0. 04 3.26 418 .26 8761 . 0. 201 � 0.23 0 . 03 1.70 416.70 3604 . 0 . 083 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 0.21 0. 15 ******** 0.34 0.31 2 0. 19 0. 07 ******** ******* 0.24 3 0. 15 0. 09 ******** ******* 0. 19 4 0. 13 0. 07 ******** ******* 0. 17 5 0. 13 0.08 ******** ******* 0. 15 6 0. 08 0.05 ******** ******* 0. 10 7 0. 04 0. 06 ******** ******* 0. 08 8 0 . 03 0. 06 ******** ******* 0. 08 ---------------------------------- Route Time Series through Facility Inflow Time Series File:chelandev.tsf Outflow Time Series File:chelanrdout POC Time Series File:chelandsout Inflow/Outflow Analysis Peak Inflow Discharge: 0.746 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.209 CFS at 15: 00 on Jan 9 in Year 8 Peak Reservoir Stage: 6.00 Ft Peak Reservoir Elev: 421.00 Ft Peak Reservoir Storage: 23116. Cu-Ft . 0.531 Ac-Ft Add Time Series:chelanbypass.tsf Peak Summed Discharge: 0.313 CFS at 9:00 on Jan 9 in Year 8 Point of Compliance File:chelandsout.tsf Flow Frequency Analysis Time Series File:chelanrdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0 . 190 2 2/09/O1 22: 00 0. 209 6.00 1 100.00 0. 990 0. 040 7 12/29/O1 11: 00 0. 190 5.62 2 25. 00 0. 960 0. 146 3 3/06/03 23: 00 0. 146 4.82 3 10.00 0. 900 0 . 0�8 8 8/�,?5/�4 6: C0 Q. 134 9 . 65 4 5 . 00 O . bC� 0 . 083 6 1/06/05 13: 00 0. 127 4 . 55 5 3. 00 0 . 667 0 . 127 5 1/19/06 4: 00 0. 083 4 . 15 6 2 . 00 0. 500 0 . 134 4 11/24/06 10:00 0. 040 3.26 7 1.30 0.231 �.209 1 1/09/08 15 : 00 0. 028 1.70 8 1 . 10 0. 091 Com�uted Peaks 0.203 5. 91 50. 00 0. 980 Flow Frequency Analysis Time Series File: chelandsout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- F1ow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period � . 236 2 2/09/O1 18 : 00 0.313 1 100.00 0. 990 C. 082 7 1/05/02 16: 00 0.236 2 25.00 0. 960 G. 186 3 3/06/03 19: 00 0 . 186 3 10.00 0. 900 0. 080 8 8/26/04 2 : 00 0 . 168 4 5.00 0. 800 0. 097 6 1/06/05 13: 00 0. 153 5 3.00 0. 667 0. 153 5 1/18/06 21: 00 0. 097 6 2 .00 0. 500 0 . 168 4 11/24/06 6: 00 0. 082 7 1. 30 0.231 0 . 313 1 1/09/08 9: 00 0. 080 8 1. 10 0. 091 Co�puted Peaks 0.287 50.00 0. 980 Flow Duration from Time Series File:chelanrdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS ° ° % - 0 0 0 0. 003 40709 66.388 66.388 33. 612 0.336E+00 0. 008 5223 8 . 518 74 . 905 25. 095 0.251E+00 0 . 013 4349 7 . 092 81. 998 18. 002 0. 180E+00 i 0. 019 3310 5.398 87 .396 12 . 604 0. 126E+00 i 0. 024 2391 3.899 91 .295 8.705 0 . 871E-01 0. 029 1978 3.226 94 . 521 5.479 0.548E-01 0. 035 1120 1.826 96.347 3. 653 0.365E-01 0. 040 1107 1. 805 98 . 152 1. 848 0.185E-01 0. 045 629 1. 026 99. 178 0. 822 0.822E-02 0. 051 85 0. 139 99.317 0. 683 0. 683E-02 0 . 056 57 0 . 093 99.410 0. 590 0.590E-02 0. 061 47 0.077 99. 486 0. 514 0.514E-02 0. 067 34 0.055 99. 542 0. 458 0. 458E-02 0. 072 21 0. 034 99. 576 0. 424 0.424E-02 0. 077 16 0. 026 99. 602 0.398 0.398E-02 0. 083 13 0. 021 99. 623 0. 377 0.377E-02 0. 088 6 0. 010 99. 633 0. 367 0.367E-02 0. 093 16 0.026 99. 659 0. 341 0.341E-02 0. 099 15 0.024 99. 684 0.316 0 .316E-02 0. 104 11 0. 018 99. 702 0.298 0.298E-02 0. 109 13 0. 021 99.723 0.277 0.277E-02 0. 114 12 0. 020 99.742 0.258 0.258E-02 0. 120 15 0.024 99.767 0.233 0.233E-02 0. 125 20 0.033 99.799 0.201 0.201E-02 , 0. 130 17 0. 028 99. 827 0. 173 0. 173E-02 0. 136 21 0.034 99.861 0. 139 0. 139E-02 0. 141 18 0. 029 99.891 0. 109 0.109E-02 0. 146 22 0 . 036 99. 927 0.073 0.739E-03 0 . 152 3 C . 005 99 . 932 0 . 068 O . o85E-03 0. 157 3 0. 005 99. 936 0 . 064 0. 636E-03 0. 162 4 0. 007 99. 943 0. 057 0.571E-03 0. 168 3 0. 005 99. 948 0.052 0.522E-03 0. 173 7 0. 011 99.959 0.041 0. 908E-03 0. 178 8 0. 013 99. 972 0.028 0.277E-03 0 . 184 5 0. 008 99 . 980 0. 020 0 . 196E-03 � . 1�9 � � . O=C °9 , u�r r. 0_C � . 9%�E-04 Flo�rr ��urGtio:� fr�;n �'--_� S�ries F'_-�: ch�l�i_asc�:_ . tsf C�atoff Count Frequency CDF Exceedence Probability CFS ° ° ° - 0 0 0 0. 003 40702 66.376 66.376 33. 624 0.336E+00 0. 010 5451 8 .889 75.266 24 .734 0.247E+00 0 . 017 4394 7 . 084 82 .350 17 . 650 0. 177E+00 0 . 023 3225 5 .259 87 .609 12 .391 0 . 124E+00 0. 030 2730 4. 452 92 .061 7 . 939 0.794E-01 0. 036 1821 2. 970 95 . 031 4. 969 0.497E-01 0. 043 1238 2 . 019 97. 050 2. 950 0.295E-01 0. 050 811 1.323 98 .372 1. 628 0.163E-01 0. 056 356 0. 581 98 . 953 1. 047 0. 105E-01 0. 063 132 0.215 99. 168 0. 832 0.832E-02 0. 069 108 0.176 99.344 0. 656 0.656E-02 0. 076 71 0 . 116 99.460 0.540 0. 540E-02 0. 083 36 0. 059 99.519 0. 481 0. 481E-02 0. 089 29 0. 047 99. 566 0. 434 0.434E-02 0. 096 23 0. 038 99.604 0. 396 0.396E-02 0. 103 22 0. 036 99. 640 0. 360 0.360E-02 0. 109 18 0. 029 99. 669 0.331 0.331E-02 0. 116 15 0.024 99. 693 0.307 0.307E-02 0. 122 17 0.028 99.721 0.279 0.279E-02 0. 129 16 0 . 026 99.747 0.253 0.253E-02 0. 136 16 0. 026 99.773 0.227 0.227E-02 0 . 142 20 0. 033 99. 806 0. 194 0. 194E-02 0 . 149 18 0.029 99.835 0. 165 0.165E-02 0 . 155 16 0.026 99.861 0. 139 0.139E-02 0. 162 18 0.029 99.891 0. 109 0. 109E-02 0. 169 14 0.023 99. 914 0. 086 0.864E-03 0. 175 7 0.011 99. 925 0. 075 0.750E-03 0. 182 6 0. 010 99. 935 0. 065 0.652E-03 0. 189 8 0 . 013 99. 948 0. 052 0.522E-03 0 . 195 7 0.011 99. 959 0. 041 0.408E-03 C .202 6 0.010 99. 969 0. 031 0.310E-03 C.208 8 0. 013 99. 982 0. 018 0.179E-03 G.215 4 0. 007 99. 989 0. 011 0. 114E-03 0 .222 2 0 . 003 99.992 0. 008 0. 815E-04 0 . 228 3 0. 005 99. 997 0. 003 0. 326E-04 0 . 235 1 0 . 002 99. 998 0. 002 C. 163E-04 -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New oChange Probability Base New oChange 0. 058 I 0. 95E-02 0. 88E-02 -7 . 9 I 0. 95E-02 0.058 0.057 -2 .0 0. 074 I 0. 63E-02 0. 51E-02 -20. 1 I 0. 63E-02 0.074 0. 066 -10. 4 0.090 I 0.49E-02 0.38E-02 -22 . 8 I 0.49E-02 0.090 0. 075 -16. 4 0 . 106 I 0.37E-02 0.30E-02 -19.8 I 0.37E-02 0 . 106 0. 091 -13. 8 0. 122 � 0.29E-02 0 .23E-02 -18 .8 I 0.29E-02 0 . 122 0. 110 -10. 1 0. 138 I 0.22E-02 0. 17E-02 -22 .1 I 0.22E-02 0. 138 0. 125 -9.4 0. 154 I 0. 15E-02 0. 11E-02 -29. 3 I 0. 15E-02 0. 154 0. 143 -6. 6 0. 169 I O. 10E-02 0.70E-03 -31 .7 I O. 10E-02 0. 169 0. 156 -8 .2 0. 185 I 0 . 62E-03 0.54E-03 -13.2 I 0. 62E-03 0. 185 0. 180 -2 .7 0.201 I 0.34E-03 0.29E-03 -14 .3 I 0.34E-03 0.201 0. 199 -1.2 0.217 I 0.23E-03 0. 13E-03 -42 . 9 I 0.23E-03 0.217 0.208 -4.3 0.233 I 0. 16E-03 0. 16E-04 -90.0 I 0. 16E-03 0.233 0.214 -8.3 0.249 I 0. 11E-03 O.00E+00 -100.0 I 0. 11E-03 0.249 0.221 -11.4 0 . 265 I 0. 16E-04 O.00E+00 -100. 0 I 0. 16E-04 0.265 0.239 -9. 9 There is no positive excursion Maximum negative excursion = 0. 016 cfs (-16.80) occurring at 0. 093 cfs on the Base Data:chelanpre.tsf and at 0. 077 cfs on the New Data:chelandsout.tsf , i ; � ,_J ( � ,-� ' � � i,_� i � I ' I -_� I �� Return Period 2 5 10 20 50 100 _ _ _ _ _ _-- _ chelanrdout.pks �n S�a-T�c • chelandsout.pks chelanbypas� � � • chelanpre.pks . • R � � . • . . 10� . • . • • � � `� o0 U _ ._ " a� rn � c� � U � 0 10"2 _ __ __ — __ — � 10-�- — — 1 2 5 10 20 30 40 50 60 70 80 90 95 98 99 Cumulative Probability � N -- ---___ _ __ o chelanrdout.dur chelandsout.dur • chelantar du� v N O � ♦ ♦ ♦ R . o � I N O ♦ � ♦ � � � � �i � � � LL U • � ♦ rn m • � � U N N 0 � � 0 4 � � � � � � _ _ __ _ .._ __ _ _.. . . _-__.. .. .. . -_. _ _.. 0 � ♦ � � �. � �0 -. .._ ._ . � - ��'--.�� -. � � • � � � 10 -5 10 -4 10 -3 10 �2 I 10 � 10° Probability Exceedence Spillway calculations Pond Emer ency Overflo�� Spill��a�r h � L Z For this ��eir Q = c 2g�2/3LH� ,+8/15zH, � (From KCSWDM 5.3.1.2) C = 0.6 discharge coefficient L = 6.00 ft (bottom width 6 feet min.) z = 3 Approximate slope h = 0.8 ft H = 0.5 ft (-0 .3' freeboard required at a min) Q = 8.17 cfs (100 Year Peak) V = 2.18 fps Filename 2013(iE.�"ERa1,..Yls Ta61�"CSPILFi't'6 16_015 !:?i P.11 Jailhouse Weir Calculations ' Based on King County SV11M FIGURE 5.3.4.E INCHES FEET CFS C L H P Q ' 3.30 36.00 6.00 6.11 3.39 v H 1 l . 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' ' --- -- / � � ----------------�'�--�_ /� _� I �\ �c---� �\� ,��'�'�� i�-�-- � ` /�' ' --�_--s__ �_ w - - — _ - -_ \� - - --_- a r --��sZ _S__ w — , ""`_"_ ---- �. .. � . . . . ' ---= � ii _�__' _ ——� __—13G-_�—S___ �N�—�*--w__ w---�,.�,—�� EzG?I4G'ti'W,4 TF?P.S��ISS�t1 NAI6 �� _- — w _�.��---h � � ,-�6 W � – �`– s� �--s----S----} ,' ,– ■ " � ' - --5-- ' �__ i--S---�- 24��kC�- --�-�-5---5---5_�IV�-B� cIH 4S�- .�� A�--S�- = Q ;' —- _ • __,4,_-�-��N-3♦-�. , – s ■�f� a��f�i��1� f��■�T V 3 � , — � � -- -- — � –'�� —_--____-�`` � � DUYALL AYE I�E `_ U _ —=� _ ' �� '�- GRAPHIC SCALE so o �o so �so WQ BASIN 1 = 0.153 AC 0.132 AC IMPERVIOUS � 0.021 AC TiLL GRASS o m ( IN FEET ) WQ BASIN 2 = 0.570 AC a v 1 inch = 60 ft. 0.380 AC IMPERVIOUS Designed: DHi 0.190 AC T1LL GRASS Drawn: DAb Checked: CMV WQ BASIN 3 = 0.203 AC IMPERVIOUS Scale: 1"=60' WQ BASIN 4 = 0.186 AC IMPERVIOUS Date: OS/01/15 Job No,: 13040 Sheet No.: B3 1 of 1 Sheets Wetpond Sizing Worksheet � Project Name: Chelan Creek Project Number: 103�� Step 1) Determine volume factor f. Basic size............................................. f= 3 Large size............................................. f= 4.5 Step 2) Determine rainfall R for mean annual Storm j Detemine rainfall R for mean annual storm ' Rainfall................................................. 0.039 (feet) � Step 3) Calculate runoff from mean annual storm V�= (0.9A; + 0.25A�9 + 0.10A,f+ 0.01Ao9)XR A;= tributary area of impervious surface 16,553 (s� At9 = tributary area of till grass 8,276 (s� A,f= tributary area of till forest 0 (sf) j Ao9 = tributary area of outwash grass 0 (sf) R = rainfall from mean annual storm 0.039 (feet) V�=Volume of runoff from mean annual storm 662 (cfl Step 4) Calculate wetpool Volume Vb = fV� f= Volume Factor 3 Vb= Volume runoff, mean annual atorm 662 (cfl V�=Volume of the wetpool 1,985 (cfl Step 5) Determine wetpool dimensions a) Determine geometry of first cell Volume in first cell 596 (cf) Depth h 1 st cell (minus sed. Storage) 3 (feet) Determine horizontal xs area at mid-depth using 199 (sf) A mid =Vol. 1st cell/h Mid-width 14 (feet) Mid-length 14 (feet) Determine xs area at surface Z = Side slope length (_H:1V) 3 3:1 recommended 2(h/2 x Z) = 9 (feet) Dimensions of top of pond adjusted for geometrics Top width 23 (feet) Top length 23 (feet) Area of Top 533 (feet) b) Determine geometry of second cell Volume in second cell 1,390 (cfl Depth h 2nd cell 3 (feet) Determine xs area at mid-depth using 463 (sfl A mid =Vol. 2nd cell/h Mid-width 14 (feet) Mid-length 33 (feet) Determine horizontal xs area at surface Z= Side slope length (_H:1 V) 3 3:1 recommended 2(h/2 x Z) = 9 (feet) Dimensions of top of pond adjusted for geometrics Top width 23 (feet) Top length 42 (feet) , Area of Top 967 (feet) Adjustment to cells (If necessary) I� Geometry check: Overall pond L:W at mid-depth = 3:1 Pond width (mid-depth) 14 Cell 1 length (mid-depth) 14 Cell 2 length {mid-depth) 33 i Pond Length (mid-depth) = Cell 1 + Cell 2 47 L mid : W mid = 3.33 Total Wetpond Surface area required = 1,500 Total Wetpond Bottom area required = 147 _ . , � � � rn � � � � N Z � 310 29'� St.NE Ste. 101 •L i �• NW Inc. Puyall up,WA 98372 Phone: (253)848-4282 Ci��il Engineering& Surveying fax: (253)848-4278 November 17. 2015 Ron Straka, PE Surface Water Utility Manager City of Renton 10�5 South Grady Way Renton. ��':a 980�7 RE: Rec�ucst for Drainage Ac�justn�ent for Water Quality Treatment I�1enu Chelan Creek PUD King County Surface Water Design Manual Section 6.1.2 Our Job #13040 Dear Ron: On behalf of our client. JK Monarch. LI_C., CES NW'. Inc. respectfully submits this request for a drainage adjustment from the 2005 King County Surface Water Design Manual Section 6.1.1. We are requesting approval to use a Filterra0 unit for Basic Water Quality treatment. Per the City of Renton 2009 Surface Water Design Manual Amendment, treatment facilities that have been given a general use level designation (GULD) through the State Department of Ecology Technology Assessment Protocol Ecology (TAPE) program may be considered for approval for ��ater quality treatment. To assist you with your review of this application, enclosed are the following documents: 1. One llxl7 copy of the Drainage Plans and Construction Notes and Details (Sheets C4, CS and C 14) 2. Vdater Quality basins, peak flows, and Filterra sizing email provided by Chris Hass and John Megrditchian at Contech. 3. One copy of the Washington State Department of Ecology "General Use Level Designation for Basic (TSS), Enhanced, and Oil Treatment for FilterraC" dated June 2015. 4. One copy of the Filterra� Operation and Maintenance Manual. 5. One copy of the City of Renton Blanket Adjustment Memo dated June 26, 2014. The 200� King County Surface Water Design A�lanual (KCSWDl�I) does not identify the Filterra� for use in complying with Basic Treatment; therefore, we are requesting this drainage adjustment to deviate from Section 6.1. — Basic Water Quality Menu. adjustments to the standards set forth in Section 1.4 of the City of Renton 2009 Surface Water .i�luj7irul:-1 nlendrrrer�� ma}� be granted provided the following are achieved: l. Produce a compensating or comparable res�ilt that is in the public interest, AND: ?. Meet the objectives of safety, function, appearance, environmental protection, and maintainability based on sound engineering judgment. Justification: We believe that this request is consistent with the above criteria and the drainage adjustment process, and represents the minimum adjustment required to accomplish the goals of this project and the goals of the KCSWDII�L In addition, the site has constraints due to the e�isting wetland and associated buffer that limit the use of many water quality treatment methods as listed in the Basic Water Quality Menu. The following outline summarizes our justification for the drainage adjustment request: 1. The Filterra RG units will produce a comparable or better water quality treatment result as they have been approved for Basic Treatment by the Washington State Department of Ecology with the GULD approval. The FilterraC units were found to achieve greater removal of TSS and zinc than the water quality objective. 2. In addition, the FilterraC� units have received GULD approval for oil treatment which is an additional benefit to the site and adjacent wetland. Sizing calculations are provided in Section 4.0 of the Technical Information Report. Supporting references are included with this submittal. 3. The safety, function, and appearance are unaffected with this proposal. Environmental protection may be increased with the Filterra unit exceeding the minimum performance goals as set by the Washington State Department of Ecology. 4. Upon completion of the project, there are some basic maintenance obligations for these systems. Maintenance will include removing trash, degraded mulch, and accumulated debris from the filter surface and replacing the mulch layer. Site inspections w�ill determine the maintenance frequency and requirements. Please refer to Section 10.0 of the enclosed Technical Information Report for a complete Operations and Maintenance Manual. Please review this information and feel free to contact me if you have any questions or would like to meet to discuss this in any further detail. Respectfully°, �� 'i �� '�4;�b'L�� Cara Visintainer. PE Civil Project Manager enc: As Noted � I'' CHELAN CREEK PUD �� CTY OF RENTON A PORTION OF SE 1/4 NW 1/4 SECTIOM 10 TOWNSFIP 23 N.RANGE S E., �EPARTMEN��F PUBLIC WOF1K8 _ WLLAMETTE YERIDIAII�KING COUNT�,WASNINGTON ��p,m� � � o ROAD ANO DRAINAGE PLAN•ONSITE GRAPHIC SCALE LUA�OB 087 �n �� a � ' PERYIT.U1S00517� - ' �s rme n x' � CON7ROL S7RUCNRE• OUD. 39 lf 12'ADS N-12 ROUIO.LO(XINC UD •-9.595 F t IucL�30�tc �� I, q11:17].00 g.E OEfAII �, LE=qS00 IN(1Y� �s�� LE:l1S00 WT(it� S�E 4EET OETAII ON 91FET C6. y S WU=��P�._< � •.___ ' ' ; t;{ 'A:f,l ;,e �1.C[_ . ,Fp~p s� aX FnF�E . _ � _. _ �Ul.19: G b '� � `, � - �35109a-C�00 eo� :i4 ;1-= . W.--' .. �"5�' __ . _ ___ rQF 12'ADS N-�2 .' 1 �:.�". �� . \ � WAMKIN(FEMCf � 771F IY AJS " � \\� _ 2 12•�/05 �� '�__ ___ N . ; _ 0�.881 ... _ < 2 � � `, � � PEN DE1/JL , N-12�5.675 , I .. N-�2 0 O.SOx ,-" i W z .. _... 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'�w . .... � �,�:s.,:e— r .� ,,, ° - '��YR �n �p . �.,� ��;< - J �`} x < AS:H�1"�qOiE1F� ��' CUAB MID pli'ER � � 'ER cA�Y=NT CUSS B CRU9�ED SUR�ApNG 'ER]EIUL.91EE-C7 ' W 1'COYP�CiEO ��Y GRAYEL BASE�' a � �EP'F M�NMW CpIPAC7ED O:P1N COMPACIFD YNiYUY 41N�YW DEVM � Z '(� FILTERRAUNIT#1 FILTERRAUNIT#2 FILTERRAUNIT#3 J s-a�cn�ae io r s.a�o.�a=o a s.A_c-��o a ,� TRACT'C'DRIYENIAY�lIIYATE ACCESSI {�J � J W�'ERp.ILLIIViLOWM'Elct O.Ot) WATE30..K.'"c.,OnRA'E�c4 ' OL]� WATEROu/�Li"aOWMIE W O.WI N.T.S W y = P:l�n�_ONMTE<'y�` �.t]5 vE4t FLOW M'E'�'ds ON PEMROVr RAi_.t tl� 031P W R_'UFN CER��]OF�FAN�,dN� 10p RETURM1 PERiW Of GEI1K FLO'N'� 10p RETURH GEiIOJ OF PEAN FLOW 100 � � � REOJ�EJM=OANFLTMTIONM'E 35 REOUREDMEJIAIVFi�Tp/�11pNRqTE 35 REpLIRE�IEDUNRTRATONiATE 15 � O ` P��'E JA'A i E. 1M'ERVLDUWETER�i�E JA'r� I.E 'NATE4 DVIETEN PIPE WTA .E. 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NF 1'.'3.�5 �SP1�A�T COM�tE'E .ao�No i3oae.0 PFYDENT CLASS 8 r ca��chu CALL 48 HOURS <e�N: °EPTM""'"1° BEFORE YOU DIG � C14 DIAL 811 •. ,5 s,e��s Contech Engineered Solutions LLC C�� "��1515 NE Glenn VJid�ng�� Portland,OR 9-: ENGINEERED SOLUTIONS ��h��conceonEs�� November 17, 2015 Cara Visintainer P.E. C.E.S. NW, Inc. 310 29'h St NE, Suite 101 Puyallup. WA 98372 Re: Chelan Creek PUD Ms. Visintainer: Contech Engineered Solutions, LLC has reviewed the plans prepared by C.E.S. NW Inc. dated (11/13/15) for the Chelan Creek PUD Project. Based on the information provided for review, Contech agrees that the Filterra system(s) designed for the project meet the Filterra General Use Designation Level (GULD) per the Technology Acceptance Protocol — Ecology (TAPE) program and that the following requirements are satisfied: 1. The water quality volume(WQv)will be evenly dispersed, allowing adequate contact time with Filterra's proprietary bioretention media per the Washington Department of Ecology's requirements and as modeled through V1N1lHM. 2. Treatment of 91% annual runoff volume is provided as required by TAPE and allowed in the Fiiterra GULD. 3. Bypass is provided through an approved mechanism: distributionlpiping system replicated from the Filterra Internal Bypass—downstream catchbasin 4. All other components of the Filterra system are specified including impermeable walls, media depth, mulch layer. and approved plants. As a result, Contech agrees that this project meets the design requirements outlined in the Filterra GULD issued by Ecology. We are pleased to work with you on this project and look forward to our continued interactions throughout the planning and installation process. Please let me know if we can be of additional assistance. Sincerely, John Megrditchian Stormwater Designer EI Contech Engineered Solutions, LLC wwxi�2 oi2 PROJECT REPORT Project Name: 13040 �i=�erra 1 Site Name: Site Address: City . Report Date: 11/17/2015 Gage : Seatac Data Start : 1948/10/O1 Data End : 2009/09/30 Precip Scale: 1.00 Version : 2G15/06/30 PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No ' Pervious Land Use Acres C, Forest, Flat .153 Pervious Total 0.153 Impervious Land Use Acres , Impervious Total 0 Basin Total 0.153 Element Flows To: Surface Interflow Groundwater MITIGATED LAND USE Name . �asin 1 � Bypass: '•]o GroundWater: td�� Pervious Land Use Acres C, Lawn, Flat .021 Pervious Total 0.021 Impervious Land Use Acres ROADS FLAT 0.132 Impervious Total 0.132 Basin Total 0.153 Element Flows To: Surface Interflow Groundwater Sazd Filter _ Sar_d F_l�er 1 Name : Sar_a Fi_ter 1 Bottom Length: 4 .00 ft. Bottom Width: 4 .00 ft. Depth: 0.?5 ft. Side slope 1: 0 To 1 Side slope 2: 0 To 1 Side slope 3: 0 To 1 Side slope 4: 0 To 1 Filtration On Hydraulic conductivity: ?0.°2 Depth of filter medium: 1.8 Total Volume Infiltrated (ac-ft) : ,_8 . 497 Total Volume Through Riser (ac-ft) : 0.113 Total Volume Through Facility (ac-ft) : 18.61 Percent Infiltrated: 99.3G Total Precip Applied to Facility: 0 - Total Evap From Facility: 0 Discharge Structure Riser Height: 0.? ft. Riser Diameter: �2 -n. Element Flows To: Outlet 1 Outlet 2 Sand Filter Hydraulic Table Stage(ft) Area(ac) Volume(ac-ft) Discharge(cfs) Infilt(cfs) O.0000 0.000 O. CGO 0.000 0 .000 0.0083 0.000 0. 000 0.000 0.02E ' O.Oi67 0.000 0.000 0.000 0.026 � 0.0250 0.000 0.000 0.000 0.02E i O.C333 0.000 0.000 0.000 0.025 O.C417 0.000 0.000 0.000 0.02c O.C500 0.000 0. 000 0.000 0.02^ O.C583 0.000 0.000 0.000 0.02^ 0.0667 0.000 0.000 0.000 0.02^ 0.0750 0.000 0.000 0.000 0.02^ 0.0833 0.000 0.000 0.000 0.02^ 0.0917 0.000 0. 000 0.000 0.02^ 0.1000 0.000 0. 000 0.000 0.02^ 0. 1083 0.000 0.000 0.000 0.02^ -- 0. 1167 0.000 0.000 0.000 0.02�c 0 . 1250 0.000 0.000 0.000 0.02'= 0. 1333 0.000 0.000 0.000 0.02'= ' ' C . 1417 O.00O 0.000 0.000 0.02'= 0. 1500 0.000 0.000 0.000 0.02'= C. 1583 0.000 0.000 0.000 0.02'= C. 166`7 0.000 0.000 0.000 0.02E C . 1?50 C .00O 0.000 Q.00O 0.028 C . 1833 � .00O �.CO� O.00G � .02c ��'.1y1� C'. �U� �� .'J;;U ... ��i�U � . �Gy 0.2000 0.000 0.000 0.000 0.029 0.2083 0.000 0.000 0.000 0.029 0.2167 0.000 0.000 0.000 0.029 0.2250 0.000 0.000 0.000 0. 029 0.2333 0.000 0.000 0.000 0. 029 0.2417 0.000 0.000 0.000 0.029 0.2500 0.000 0.000 0.000 0.02° 0.2583 0.000 0.000 0.000 0.030 0.2667 0.000 0.000 0.000 0.030 0.2750 0.000 0.000 0.000 0. 030 0.2833 0.000 0.000 0.000 0. 030 0.2917 0.000 0.000 0.000 0. 030 0.3000 0.000 0.000 0.000 0.030 0.3083 0.000 0.000 0.000 O.C3'` 0.3167 0.000 0. 000 0.000 0.��:� 0.3250 0.000 0.000 0.000 O. C31 0.3333 0.000 0.000 0.000 O. C31 0.3417 0.000 0.000 0.000 O. C�l 0.3500 0.000 O.000 0.000 O. C�l 0.3583 0.000 0.000 0.000 O. C}1 �.3667 0.000 O.000 0.000 O.C�l �.3750 0.000 0.000 0.000 O.C31 ' �.3833 0.000 0.000 0.000 O.C31 �.3917 0.000 0.000 0.000 O.Cj2 : .4000 0.000 0.000 0.000 O.C �� . 4083 0.000 0.000 0.000 O. C-'�% 0.4167 0.000 0.000 0.000 O. C3- 0. 4250 0.000 0.000 0.000 O.C�% 0.4333 0.000 0.000 0.000 0.03z � 0.4417 0.000 0.000 0.000 0.032 0.4500 0.000 0.000 0.000 O.G�2 0.4583 0.000 0.000 0.000 O.Q?;� 0.4667 0.000 0.000 0.000 O.Q:!� 0.4750 0. 000 0.000 0.000 O.G�� 0.4833 0. 000 0.000 0.000 0.03? 0. 4917 0. 000 0.000 0.000 O.G?� 0.5000 0.000 0.000 0.000 O.G"? � 0.5083 0.000 0.000 0.000 0.0:?� 0.5167 0.000 0.000 0.000 0.0'� 0.5250 0.000 0.000 0.000 0.0�� 0.5333 0.000 0.000 0.000 O.G34 0.5417 0.000 0.000 0.000 0.03� 0.5500 0.000 0.000 0.000 0.0�� 0.5583 0.000 0.000 0.000 0.0?' 0.5667 0.000 0.000 0.000 0.0?= 0.5750 0.000 0.000 0.000 0.0�= 0.5833 0.000 0.000 0.000 0.0?= 0.5917 0.000 0.000 0.000 0.0?= 0.6000 0.000 0.000 0.000 0.0�� 0.6083 0.000 0.000 0.000 0.0�� 0.6167 0.000 0.000 0.000 0.�35 0. 6250 0. 000 0.000 0.000 0. �� 0. 6333 0. 000 0.000 0.000 0. 0�� 0.6417 0. 000 0.000 0.000 O. C3r: 0. 6500 0.000 0.000 0.000 O. C35 0. 6583 0.000 0.000 0.000 O. C��`.. 0. 6667 0.000 C.000 0. 000 O. C =F" _ . � ��"� 0. � ; � ._i;_ �`. "C _' . _ ,r �.6833 �.00G O.QUC O.000 0.030 0.6917 0.000 0.000 0.000 0.036 0.7000 0.000 0.000 0.000 0.036 0.7083 0.000 0.000 0.008 0.036 0.7167 0.000 0.000 0.022 0.036 0.7250 0.000 O.00C 0.041 0.036 0.7333 0.000 0.000 0.064 0.03- 0.7417 0.000 0.000 0.090 0.03? 0.7500 0.000 0.000 0.118 0.03? 0.7583 0.000 O.000 0.149 0.03? ANALYSIS RESULTS Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.153 Total Impervious Area:O Mitigated Landuse Totals for POC #1 ' Total Pervious Area:0.021 Total Impervious Area:0.132 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year O.009� 5 year 0.007CEa 10 year 0.008529 25 year 0.010067 50 year 0.011022 100 year 0.011834 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.033639 5 year 0.075275 10 year 0. 105129 25 year 0. 191439 50 year 0. 166236 100 year 0. 188?C5 Perind and Impind Changes No cranges have been -�.ade. This program ard accompanying documentation are provided 'as-is' without orarrar.�y of ary }:_�d. Tte entire risk regardinq the performance and results of this program is assumed by End User. Clear Cre2?_ Solutions Inc. and the governmer.tal licensee or sublicersees discla-�r.iall warranties, either expressec or ir�plied, including but r.ct limited to implied warranties of program and accor�panying documentation. In no event shal'_ Clear Creek Soiutions Inc. be liable for any damages whatsoever (including withou� limitation to damages for loss of business profits, loss of business information, business , interruption, and the li:�ce? arising out of the use of, or inability to use this program even if Clear Cre�>: Scictiors -._. _� treir authc_'_�ed represe�tati�:;es ha�.-e tieer. ad.�is�d r'_ tr� pc,ss-^il:t.; of =c�� .G-r.:r_a. c t-.:�� ___ -g�= b�, . �� ._: � L-i�- , .._ �� J1`_, . -- � - '-' _rv��,�. wwxiK2 o i 2 PROJECT REPORT Project Name: 1�040 �i-�e�ra 2 Site Name: Site Address: City . Report Date: _1/1?/2C�5 Gage : Seatac Data Start : '�948/1`�i%C_ Data End : 2009/09/3=, Precip Scale: 1.00 Version : 2015/06i : PREDEVELOPED LAND USE Name . B�sir :� Bypass: P�1� GroundWater: ��I�� ' Pervious Land Use Acres C, Forest, Flat .203 Pervious Total 0.203 Impervious Land Use Acres Impervious Total 0 Basin Total 0.203 Element Flows To: Surface Interflow Groundwater MITIGATED LAND USE Name . �,z�--a Bypass: _:_ GroundWater: :�_ Pervious Land Use Acres Pervious Total 0 Impervious Land Use Acres ROADS FLAT 0.203 Impervious Total 0.203 Basin Total 0.203 Element Flows To: Surface Interflow Groundwater Sar_d ��_lter 1 Sand =iiter - Name . �u:i� _-1t�_ _ Bottom Length: 4 . 0:�� -t . Bottom Width: ` . CO t� , Depth: �.?5 f� . Side slope 1: G Tc : Side slope 2: G Tc - Side slope 3: 0 To "� Side slope 4: 0 To 1 Filtration On Hydraulic conductivity: 7G.°2 Depth of filter medium: l.� Total Volume Infiltrated (ac-ft) : 28 . 414 Total Volume Through Riser (ac-ft) : 0.58� Total Volume Through Facility (ac-ft) : 29 Percent Infiltrated: 9; . 98 Total Precip Applied to Facility: 0 ' Total Evap From Facility: 0 Discharge Structure Riser Height: 0.7 ft. Riser Diameter: 12 _n. Element Flows To: Outlet 1 Outlet 2 Sand Filter Hydraulic Table Stage(ft) Area(ac) Volume(ac-ft) Discharge(cfs) Infilt(cfs) C . ��CO O.00O O.00C 0.000 � .000 0.0083 0.000 0.000 0.000 0.026 O.C167 0.000 0.000 0.000 0.026 O.C250 0.000 0.000 0.000 0.026 O.C333 0 .000 0.000 0.000 0.026 0.0917 0.000 0.000 0.000 0.026 0.0500 0.000 0.000 0.000 0.027 0.0583 0.000 C.000 0.000 0.027 0.066� C.000 0.000 0.000 C.02� 0.0750 0.000 O.00O 0.000 0.027 0.0833 0. 000 C.000 0.000 0.027 0.09,�7 0.000 0.000 0.000 0. 027 O.1C00 0.000 0.000 0. 000 0.027 0.1083 0.000 0.000 0. 000 0. 027 O.i167 0.000 0.000 0. 000 0.028 0.1250 0.000 0.000 0. 000 0.028 0.1333 0.000 0.000 0. 000 O.C28 0.1417 0.000 0.000 0.000 0.028 0.1�00 0.000 0.000 0.000 0.028 0.1583 0.000 0.000 0.000 0.02� 0.1667 0.000 0. 000 0.000 0.028 0 . 1750 0.000 0. 000 0.000 0.028 0 . 1833 0.000 O. 000 0.000 0.028 � . 1917 0.000 O.000 0.000 0.02° � .�OCO 0.000 O. CO� Q.0�0 0.029 �; .2u83 0.000 C�.00G O. O�C . �-�� .2167 0.000 0.000 O. O�G ;; . �� .2250 0.000 0.000 0.000 0. 02° 0.2333 0.000 0.000 0.000 0. 02� C .2417 0.000 0.000 0.000 0 . 02� C .2500 0.000 0.000 0.000 0.02° C .2583 0.000 O.00O 0.000 0 .03=� C .2667 0.000 0.000 0.000 0.03�% C.2750 0.000 0.000 0.000 0.03�� C.2833 0.000 0.000 0.000 0.0.�� C.2917 0.000 0.000 0.000 0.03�� G. 3000 0.000 0.000 0.000 0.03�� C.3083 0.000 0.000 0.000 0.03�� 0. 3167 0. 000 0.000 0.000 0.030 0. 3250 0.000 0.000 0.000 0.031 0. 3333 0.000 0.000 0.000 0.031 0. 3417 0.000 0.000 0.000 0.03,i 0. 3500 0.000 0.000 0.000 O.Os1 0. 3583 0.000 0.000 0.000 0.031 0. 3667 0.000 0.000 0.000 0.031 0. 3750 0.000 0.000 0.000 0.031 0. 3833 0. 000 0.000 0.000 0.031 0.3917 0. 000 0.000 0.000 0.032 , 0.4000 0. 000 0.000 0.000 0.032 0.4083 0. 000 0.000 0.000 0.032 0.4167 0. 000 0.000 0.000 0.032 0.4250 0. 000 0.000 0.000 0.032 0.4333 0. 000 0.000 0.000 0.032 0.4417 0. 000 0.000 0.000 0.032 0.9500 0. 000 0.000 0.000 0.032 0.4583 0. 000 0.000 0.000 0.033 0.4667 0.000 O.00O 0.000 0.033 0.4750 0.000 0.000 0.000 0.033 0.4833 0.000 O.00O 0.000 0.033 0.4917 0.000 O.00O 0.000 0.033 0.5000 0.000 O.00O 0.000 0.033 0.5083 0.000 O.00O 0.000 0.033 0.5167 0.000 O.00O 0.000 0.033 0.5250 0.000 O.00O 0.000 0.033 0.5333 0.000 0.000 0.000 0.034 �.5417 0.000 0.000 0.000 0.034 �.5500 0.000 0.000 0.000 0.034 0.5583 0.000 0.000 0.000 0.034 0.5667 0.000 0.000 0.000 0.039 C.5750 0.000 0.000 0.000 0.034 C.5833 0.000 O.000 0.000 0.034 0.5917 0.000 0.000 0.000 0.034 0. 6000 0.000 0.000 0.000 0.035 0. 6083 0.000 0.000 0.000 0.035 0. 6167 0.000 0.000 0.000 0.035 0.6250 0.000 0.000 0.000 0.035 0. 6333 0.000 0.000 0.000 0 .035 O. e417 0.000 0.000 0.000 0.035 O. n�00 0.000 0.000 0.000 0.035 0. 6583 0.000 0.000 0.000 0. 035 �i. o667 0. 000 0.000 0.000 0. 036 :� . c?50 0. 000 0.000 0.000 0. 036 =� . c833 0. 000 0.000 0.000 0. 036 _ . c91? O. 00C � .n��0 0. ^00 C. 035 i 0.7000 0.000 0.000 0.000 0.036 0.7083 0.000 0.000 0.008 0.036 0.7167 0.000 0.000 0.022 0.036 0.�250 0.000 0.000 0.041 0.036 0.�333 0.000 0.000 0.064 0.037 0.7417 0.000 0.000 0.090 0.037 0.7500 0.000 0.000 0.118 0.037 0.7583 0.000 0.000 0. 149 0.037 ANALYSIS RESULTS Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.203 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:O I Total Impervious Area:0.203 ' Flow Frequency Return Periods for Predeveloped. POC #1 �, Return Period Flow(cfs) I 2 year O.C�39=1 ! 5 year O.006144 10 year 0.00741 25 year 0.008751 50 year O.009581 100 year O.C1028? Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year O.C38864 5 year 0.059977 10 year 0.075246 25 year 0.095835 50 year 0.112041 100 year 0.128947 Perind and Impind Changes No changes :�ave been made. This program and acccmpa:'iying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the perfcrr�ance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or subiicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompany�ng documentation. In no event shall Clear Creek So��utions Inc. be liable for any dar,iages whatsoever (ir.cluding without limitation to damages for lcss of business profits, loss of business information, business interruption, and the like) arisinq out of the use of, or inability to ase this prograr.iever. if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright .s by : Ciear Creek Soiutions, Inc. 20G5-2015; All Rights Reserved. wwi�t2 012 PROJECT REPORT Project Name: 13��' Filterra � Site Name: Site Address: City . Report Date: il/li%2C=�. Gage : Seatac Data Start : 1948/10/Ol Data End : 2009/09/3C ', Precip Scale: 1.00 � Version : 20-5/06/3C PREDEVELOPED LAND USE Name : Bas-n - Bypass: DIo GroundWater: No � Pervious Land Use Acres C, Forest, Flat .186 Pervious Total 0.186 Impervious Land Use Acres Impervious Total 0 Basin Total 0.186 Element Flows To: Surface Interflow Groundwater MITIGATED 7,AND USE Name : Basin 4 Bypass: I�Io GroundWater: No Pervious Land Use Acres Pervious Total 0 Impervious Land Use Acres ROADS FLAT 0.186 Impervious Total 0.186 Basin Total 0.186 Element Flows To: Surface Interflow Groundwater Sand �'_lter 1 SGnd Fi�ter "� j Name : Sand Filter = Bottom Length: 4 .00 f= . Bottom Width: 4 .00 rt. ' Depth: 0.?5 ft. i Side slope 1: 0 To '_ Side slope 2: 0 To i Side slope 3: 0 To 1 ' Side slope 4: 0 Tc _ Filtration On Hydraulic conductivity: ;_ . Depth of filter medium: l. c Total Volume Infiltrated (ac-ft) : �� . `_��-_ Total Volume Through Riser (ac-ft) : 0. 4L Total Volume Through Facility (ac-ft) : %e . ,_- Percent Infiltrated: 93.4� Total Precip Applied to Facility: ?� Total Evap From Facility: " Discharge Structure Riser Height: 0.? -- . - Riser Diameter: 1:' -_.. Element Flows To: Outlet 1 Outlet 2 Sand Filter Hydraulic Table Stage(£t) Area(ac) Volume(ac-ft) Discharge(cfs) Infilt(cfs) O. ��CO 0.000 O.GOC 0.000 G.G�,- C.0083 0.000 0.000 O.00O 0.026 0.0167 0.000 0.000 0.000 0. 02t; 0.0250 0.000 0.000 0.000 0.02F� 0.0333 0.000 0. 000 0.000 0.02F: 0.0417 0.000 0.000 0.000 0.02F 0.0500 0.000 0.000 0.000 0.02� 0.0583 0. 000 0.000 0.000 0.02- 0.0667 0.000 0.000 0.000 0.02"; '� 0.0750 0.000 0.000 0.000 0.027 0.0833 0.000 0.000 0.000 0.02? 0.0917 0.000 0.000 0.000 0.02? 0.1000 0.000 O.00C 0.000 0. 02? 0.1083 0.000 0.000 0.000 C. 02? 0.1167 0.000 0.000 0.000 0.028 0.1250 0.000 0.000 0.000 0.02„; 0.1333 0.000 0.000 C.000 0.02� 0. 1417 0.000 0.000 0.000 0.02c 0. 1500 0.000 0.000 0.000 0.02� 0. 1583 0.000 0.000 0.000 0.02c 0. 1667 0.000 0.000 0.000 0.02� 0. 1750 0.000 0.000 0.000 0.02� 0. 1833 0.000 0.000 0.000 0.02� 0.1917 0.000 0.000 0.000 0.02'N - 0.2000 0.000 C.000 0.000 0. 02'4 n.2QR3 C. �00 r_, .n�0 0.000 O. C2�= 0.216� 0.000 0.000 0.000 0.029 0.2250 0.000 0.000 0.000 0.029 0.2333 0.000 0.000 0.000 0.029 0.2917 0.000 0.000 0.000 0.029 0.2500 0.000 0.000 0.000 0.029 0.2583 0.000 0.000 0.000 0.030 0.266� 0.000 0.000 0.000 0.030 0.2750 0.000 0.000 0.000 0.030 0.2833 0.000 0.000 0.000 0.030 0.2917 0.000 0.000 0. 000 0.030 0.3000 0.000 0.000 0.000 0.030 0.3083 0.000 0.000 0.000 0.030 0.3167 0.000 0.000 0.000 0.030 0.3250 0.000 0.000 O.000 0.031 0.3333 0.000 0.000 0.000 0.031 0.3917 0.000 0.000 0.000 0.031 0.3500 0.000 0.000 0.000 0.031 0. 3583 0.000 0.000 0.000 0.031 0. 3667 0.000 0.000 0.000 0.031 0.3750 0.000 0.000 0.000 0.031 0.3833 0.000 0.000 0.000 0.031 0.3917 0.000 0.000 0.000 0.032 , 0.4000 0.000 0.000 0.000 0.032 � 0. 4083 0.000 0.000 0.000 0.032 0.4167 0.000 0.000 0.000 0.032 0.4250 0.000 0.000 0.000 0.032 0.4333 0.000 0.000 0.000 0.032 ' 0.4417 0.000 0.000 0.000 0.032 0. 4500 0.000 0.000 0.000 0.032 0. 4583 0.000 0.000 0.000 0.033 0.4667 0.000 0.000 0.000 0.033 0.4750 0.000 0.000 0.000 0.033 0.4833 0.000 0.000 0.000 0. 033 0.4917 0.000 0.000 0.000 0. 033 0.5000 0.000 0.000 0.000 0.033 0. 5083 0.000 0.000 0.000 0.033 0.5167 0.000 0.000 0.000 0.033 0.5250 0.000 0.000 0.000 0.033 0.5333 0.000 0.000 0.000 0.034 0.5417 0.000 0.000 0.000 0.039 0. 5500 0.000 0.000 0.000 0.034 0.5583 0.000 0.000 0.000 0.034 0.5667 0.000 0.000 0.000 0.034 , 0.5750 0.000 0.000 0.000 0.034 _ 0. 5833 0.000 0.000 0.000 0.034 0.5917 0.000 0.000 0.000 0.034 0.6000 0.000 0.000 0.000 0.035 0. 6083 0.000 0.000 0.000 0.035 0.616� 0.000 0.000 0.000 0.035 0.6250 0.000 0.000 0.000 0.035 0. 6333 0.000 0.000 0.000 0.035 0. 641� 0.000 0.000 0.000 0.035 0.6500 0.000 0.000 0.000 0.035 0. 6583 0.000 0.000 0.000 0.035 0. 6667 0.000 0.000 0.000 0.036 0. 6750 0. 000 0.000 0.000 0.036 0.6833 0.000 0.000 0.000 0.036 0. 6917 0.000 0.000 0.000 0.036 0.7000 0.000 0.000 0.000 0.036 0.7083 0.000 0.000 0.008 0.036 0.7167 0.000 0.000 0.022 0.036 0.7250 0.000 0.000 0.041 0.036 0.7333 0.000 0.000 0.064 0.037 0.7917 0.000 0.000 0.090 0.037 0.7500 0.000 0.000 0.118 0.037 0.�583 0.000 0.000 0.149 0.037 ANALYSIS RESULTS Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.186 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:O Total Impervious Area:0.186 Flow Frequency Return Periods for Predeveloped. POC #1 ' Return Period Flow(cfs) 2 year �.0�� 5 year �.G�8�N.s 10 year �.010363 25 year �.012239 50 year �.013399 100 year �.014386 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs] 2 year �.0324C2 5 year 0.052315 10 year 0.066477 25 year 0.085139 50 year 0.099459 100 year 0.114054 Perind and Impind Changes No changes have been made. Th�s program and accompanyir.q dccur�entation are provideci 'as-is' aitheut warranty of any kir.d. The entire risk regarding the performance and results cf this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disciaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek So�utior.s Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability tc use this prcgram even if Clear Creek Solutior.s Inc. or their authorized representatives have beer, advised of the possibility of such damaqes. Software Copyright :, by : Clear Creek Solutions, Inc. 2005-2015; All Riqhts Reserved. �� W1S1�' � <IATE oEr � � iu :�vi oF E C 0 L 0 C Y June2015 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS), ENHANCED, , PHOSPHORUS & OIL TREATMENT 'i CONDITIONAL USE LEVEL DESIGNATION FOR BASIC AND ENHANCED AT 100 IN/HR � For I Americast Filterra'N' Ecolo�v's Decision: Based on Americast's submissions, including the application dated May 15, 2015, Final Technical Evaluation Reports, dated March 27, 2014, December 2009 and additional information provided to Ecology dated October 9, 2009, Ecology hereby issues the foilowing use level designations: ' 1. A General Use Level Designation for Basic, Enhanced, Phosphorus, and Oil Treatment at the following water quality design hydraulic loading rates: Treatment Hydraulic Conductivity* Infiltration Rate (in/hr) for (in/hr) for use in Western use in eastern Washington Washington Sizing Sizing Basic 70.92 100 Phosphorus 7092 1 QO Oil 35.46 50 Enhanced 24.82 35 *calculated based on listed infiltration rate and a hydraulic gradient of 1.41 inch/inch. 2. A Conditional Use Level Designation for Basic and Enhanced Treatment at the following water quality design hydraulic loading rates: Treatment Hydraulic conductivity* Infiltration Rate (in/hr) for {inThr) for use in Western use in Eastern Washington Washington Sizing Sizing Basic 70.92 100 Enhanced 70.92 100 3. The Filterra � unit is not appropriate for oil spill-control purposes. 4. Ecology approves the Filterra�units for treatment at the hydraulic loading rates listed above, to achieve the maximum water quality design flow rate. Calculate the water quality design flow rates using the following procedures: 1 • Western Washington: for treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using the sand filter module in the latest version of the Western Washington Hydrology Model or other Ecology-approved c�ontinuous runoff model. The model must indicate the unit is capable of processing 91 percent of the influent runoff file. • Eastern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using one of the three flow rate based methods described in Chapter 2.2.5 of the Stormwater Management Manual for Eastern Washington(SWMMEW) or local manual. • Entire State: For treatment installed downstream of detention, the water quality design flow rate is the full 2-year release rate of the detention facility. 5. This General Use Le��el Designation has no expiration date but Ecology may revoke or amend the designation, and is subject to the conditions specified below. 6. The Basic and Enhanced CULD expires on June 30, 2018 unless extended by Ecology. Ecolo�v's Conditions of Use: � FilterraCR� units shall comply with these conditions shall comply with the following conditions: l. Design, assemble, install, operate, and maintain the Filtena�units in accordance w�th applicable Americast Filterra� manuals, document, and the Ecology Decision. 2. Each site plan must undergo Americast Filterra�J review before Ecology can approve the unit for site installation. This will ensure that site grading and slope are appropriate for use of a � Filterra�unit. 3. Filterra RO media shall conform to the specifications submitted to and approved by Ecology. 4. Maintenance includes removing trash, degraded mulch, and accumulated debris from the filter surface and replacing the mulch layer. Use inspections to determine the site-specific maintenance schedules and requirements. Follow maintenance procedures given in the most recent version of the Filterra�� Operation and Maintenance Manual. , 5. Maintenance: The required maintenance interval for stormwater treatment de��ices is often - dependent upon the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a"one size fits all" maintenance cycle for a - particular model/size of manufactured filter treatment device. j • Filterra designs their systems for a target maintenance inten-al of 6 months. Maintenance � includes removing accumulated sediment and trash from the surface area of the media, _ removing the mulch above the media, replacing the mulch, providing plant health ' evaluation, and pruning the plant if deemed necessary. • Conduct maintenance following manufacturer's guidelines. 6. FilterraOO units come in standard sizes. I � 7. The minimum size filter surface-area for use in western Washington is determined by usin`� the sand filter module in the latest version of WWHM or other Ecology approved continuous runoff model for western Washington. Model inputs include a) Filter media depth: 1.8 feet b) Effective Ponding Depth: 0.75 feet (This is equivalent to the 6-inch clear zone between the top of the mulch and the bottom of the slab plus 3-inches of mulch.) c) Side slopes: Vertical d) Riser height: 0.70 feet e) Filter Hydraulic Conductivity: Use the Hydraulic Conductivity as listed in the table above (use the lowest applicable hydraulic conductivity depending on the level of treatment required) under Ecology's Decision, above. 8. The minimum size filter surface-area for use in eastern Washington is determined by using the design water qualiry flow rate (as determined in item 3, above) and the Infiltration Rate from the table above (use the lowest applicable Infiltration Rate depending on the level of treatment required). Calculate the required area by dividing the water quality design flow rate "-� (cu-ft/sec) by the Infiltration Rate (converted to ft/sec) to obtain required surface area (sq ft) of the Filterra unit. 9. Discharges from the Filterra� units shall not cause or contribute to water quality standards ' violations in receiving waters. 10. Contech commits to submitting a QAPP for Ecology approval by October 1, 2015 that meets the TAPE requirements for attaining a GULD for Basic and Enhanced Treatment 11. Contech shall complete all required testing and submit a TER on TSS and dissol��ed metals removal far Ecology's review by December 31, 2017 12. Contech may request Ecology to grant deadline or expiration date extensions, upon showing cause for such extensions. Apnroved Alternate Confi�urations Filterra'�Internal Bypass - Pipe (FTIB-P) 1. The Filterra� Internal Bypass—Pipe allows for piped-in flow from area drains, grated inlets, trench drains, and/or roof drains. Design capture flows and peak flows enter the structure i . through an internal slotted pipe. Filterra� inverted the slotted pipe to allow design flows to drop through to a series of splash plates that then disperse the design flows over the top j ': surface of the Filterra�planter area. Higher flows continue to bypass the slotted pipe and � convey out the structure. 2. To select a FTIB-P unit, the designer must determine the size of the standard unit using the sizing guidance described above. Filterrag Internal Bypass—Curb (FTIB-C) 1. The Filterra� Internal Bypass—Curb model (FTIB-C) incorporates a curb inlet, biofiltration treatment chamber, and internal high flow bypass in one single structure. FilterraOO designed the FTIB-C model for use in a"Sag' or"Sump" condition and��ill accept flows from both directions along a gutter line. An internal flume tray weir component directs treatment flo«s entering the unit through the curb inlet to the biofiltration treatment chamber. Flows in excess of the water quality treatment flow rise above the flume tray weir and discharge through a standpipe orifice; providing bypass of untreated peak flows. Americast manufactures the FTIB-C model in a variety of sizes and configurations and you may use the unit on a continuous grade when a single structure providing both treatment and high flow �', bypass is preferred. The FTIB-C model can also incorparate a separate junction box chamber �i to allow larger diameter discharge pipe connections to the structure. � 2. To select a FTIB-C unit, the designer must determine the size of the standard unit using the ' sizing guidance described above. Filterra�' Shallow 1. The FilterraG Shallow provides additional flexibility for design engineers and designers in ' situations where there is limited depth and various elevation constraints to applying a standard Filterra RG configuration. Engineers can design this s}rstem up to six inches shallower than any of the previous Filtena unit configurations noted above. 2. Ecology requires that the Filterra� Shallow provide a contact time equivalent to that of the standard unit. This means that with a smaller depth of inedia, the surface area must increase. 3. To select a Filterra� Shallo�J System unit, the designer must first identify the size of the _ standard unit using the modeling guidance described above. 4. Once you establish the size of the standard Filterra�unit using the sizing technique described above, use information from the following table to select the appropriate size Filterra� Shallow System unit. Shallow Unit Basic, Enhanced, and Oil Treatment Sizing Standard De th E uivalent Shallow De th 4x4 4x6 or 6x4 __.------- _...____�.__.._ ._ _ .---------------- . _ . _�-----.. . ........ .. ._---.. _.__.. 4x6 or 6x4 6x6 _. -- --- . .�. . �_ - - - - --- -- ---- - ---�------------ 4x8 or 8x4 I _ bx8 or 8x6 _ �__�...__ .-- - - - --__ . ------ ------------ 6x6 6x 10 or l Ox6 -------_._.__ _. ...___.._____..__..__.--------------<---------------_._._._._..................._.__..__._..-------._._._.._. 6x8 or 8x6 6x12 or 12x6 �_................._...._._.__.--------------�--------------------------._.._....____..------------__._._.____.__._. 6x10 or lOx6 13x7 Notes: I. Shallow Depth Bo�es are less than the standard depth of 3.5 feet but no]ess than 3A feet deep(TC to INV). 4 Applicant: Filterra�" Bioretention Systems, division of Contech Engineered Solutions, LLC. Applicant's Address: 11815 NE Glenn Widing Drive Portland, OR 97220 Application Documents: • State of Washington Department of Ecology Application for Conditional Use Designation, Americast (September 2006) • Quality Assurance Project Plan Filterra�' Bioretention Filtration System Performance Monitoring, Americast (April 2008) � • Quality Assurance Project Plan Addendum Filterra� Bioretention Filtration System Performance Monitoring, Americast (June 2008) • Draft Technical Evaluation Report Filterra'"� Bioretention Filtration System Perforniance Nlonitoring, Americast(August 2009) • Final Technical Evaluation Report FilterraR' Bioretention Filtration System Performance Nlonitoring, Americast (December 2009) • Technical Evaluation Report Appendices Filterra`�' Bioretention Filtration System ' Performance Monitoring, Americast, August 2009 • Memorandum to Department of Ecology Dated October 9, 2009 from Americast, Inc. and Herrera Environmental Consultants • Quality Assurance Project Plan FilterraR' Bioretention System Phosphorus treatment and Supplemental Basic and Enhanced Treatment Performance Monitaring, Americast (November 2011) • Filterra'R letter August 24, 2012 regarding sizing for the Filterra" Shallow System. • University of Virginia Engineering Department Memo by Joanna Crowe Curran, Ph. D dated March 16, 2013 concerning capacity analysis of FilterraR' internal weir inlet tray. • Terraphase Engineering letter to Jodi Mills, P.E. dated April 2, 2013 regarding Terraflume Hydraulic Test, Filterra� Bioretention System and attachments. • Technical Evaluation Report, Filterra" System Phosphorus Treatment and Supplemental Basic Treatment Performance Monitoring. March 27th, 2014. • State of Washington Department of Ecolog}- Application for Conditional Use Level Designation, Contech Engineered Solutions (May 2015) • Quality Assurance Project Plan FilterraOO Bioretention System, Contech Engineered Solutions (N1ay 2015) Applicant's Use Level Request: General Level Use Designation for Basic (100 in/hr), Enhanced (35 in/hr), Phosphorus (100 in/hr), and Oil Treatment (50 in/hr). Conditional Use Level Designation for Basic and Enhanced at 100 in/hr ; Applicant's Performance Claims: Field-testing and laboratory testing show that the FilterraN unit is promising as a storin��ater treatment best management practice and can meet Ecolog��'s performance goals for basic, enhanced, phosphorus, and oil treatment. Findings of Fact: Field Testin� 2013 1. Filterra� completed field-testing of a 6.� ft � 4 ft. unit at one site in Bellingharn, Washington. Continuous flow and rainfall data collected from January l, 2013 through July 23, 2013 indicated that 59 storm events occurred. The monitoring obtained water quality data from 22 storm events. Not all the sampled storms produced information that met TAPE criteria for storm and/or vvater quality data. ?. The system treated 98.9 percent of the total 8-month runoff volume during the testing ', period. Consequently, the system achieved the goal of treating 91 percent of the volume I from the site. Stormwater runoff bypassed during four of the 59 storm events. ' 3. Of the 22 sampled events, 18 qualified for TSS analysis (influent TSS concentrations ranged from 25 to 138 mg/L). The data were segregated into sample pairs with influent concentration greater than and less than 100 mg/L. The UCL95 mean effluent concentration for the data with influent less than 100 mg/L was 5.2 mg/L, below the 20- mg/L threshold. Although the TAPE guidelines do not require an evaluation of TSS removal efficiency for influent concentrations below 100 mg/L, the mean TSS removal for these samples was 90.1 percent. Average removal of influent TSS concentrations greater than 100 mg/L (three events) was 85 percent. In addition, the system consistently e�hibited TSS removal greater than 80 percent at flow rates at a 100 inches per hour [in/hr] infiltration rate and was observed at I50 in/hr. 4. Ten of the 22 sampled events qualified for TP analysis. Americast augmented the dataset using two sample pairs from previous monitoring at the site. Influent TP concentrations ranged from 0.11 to 0.52 mg/L. The mean TP removal for these twelve events ��as 72.6 percent. The LCL95 mean percent removal was 66.0, well above the TAPE requirement of 50 percent. Treatment above 50 percent was evident at 100 in/hr infiltration rate and as high as 150 in/hr. Consequently, the Filterra'R'test system met the TAPE Phosphorus Treatment goal at 100 in/hr. Influent ortho-P concentrations ranged from 0.005 to 0.012 mg/L; effluent ortho-P concentrations ranged from 0.005 to 0.013 mg/L. The reporting limit/resolution for the ortho-P test method is 0.41 mg/L, therefore the influent and effluent ortho-P concentrations ��ere both at or near non-detect concentrations. Field Testing 2008-?009 1. FilterraR" completed field-testing at t��o sites at the Port of Tacoma. Continuous flow and rainfall data collected during the 2008-2009 monitoring period indicated that 89 storm events occurred. The monitoring obtained «�ater quality data from 27 storm events. Not 6 all the sampled storms produced information that met TAPE criteria for storm and;'or ��ater quality data. ?. During the testing at the Port of Tacotna, 98.96 to 99.89 percent of the annual influent runoff volume passed through the POTI and POT2 test systems respectively. Stormwater runoff bypassed the POT1 test system during nine storm events and bypassed the POT2 test system during one storm event. Bypass volumes ranged from 0.13% to 15.3% of the influent storm volume. Both test systems achieved the 91 percent ��ater quality treatment-goal over the 1-year monitoring period. 3. Consultants observed intiltration rates as high as 133 in/hr during the various storms. Filterra� did not provide any paired data that identified percent removal of TSS, metals, oil, or phosphorus at an instantaneous observed flow rate. 4. "The maximum storm average hydraulic loading rate associated with water quality data is <40 in/hr, with the majority of flow rates <25 in/hr. The average instantaneous hydraulic loading rate ranged from 8.6 to 53 inches per hour. �. The field data showed a removal rate greater than 80% for TSS with an influent concentration greater than 20 mg/l at an average instantaneous hydraulic loading rate up to 53 in/hr (average influent concentration of 28.8 mg/1, average effluent concentration of 4.3 mgll). 6. The field data showed a removal rate generally greater than 54% for dissolved zinc at an average instantaneous hydraulic loading rate up to 60 inlhr and an average influent concentration of 0.266 mg/1 (average effluent concentration of 0.115 mg/l). 7. The field data showed a removal rate generally greater than 40% for dissolved copper at an average instantaneous hydraulic loading rate up to 35 in/hr and an average influent concentration of 0.0070 mg/1 (average effluent concentration of 0.0036 mg/1). 8. The field data showed an average removal rate of 93% for total petroleum hydrocarbon (TPH} at an average instantaneous hydraulic loading rate up to 53 in/hr and an average influent concentration of 52 mg/1 (average effluent concentration of 2.3 mg/1). The data also shows achievement of less than 15 mg/1 TPH for grab samples. Filterra'R�provided limited visible sheen data due to access limitations at the outlet monitoring location. 9. The field data showed low percentage removals of total phosphorus at all storm flows at an average influent concentration of 0.189 mg/l (average effluent concentration of 0.171 mg/1). We may relate the relatively poor treatment performance of the Filterrag' system at this location to influent characteristics for total phosphorus that are unique to the Port of Tacoma site. It appears that the Filterra'�� system will not meet the 50 percent removal performance goal vvhen you expect the majority of phosphorus in the runoff to be in the dissolved form. Laboratory Testing 1. Filterra�'performed laboratory testing on a scaled down version of the Filterrag' unit. The lab data sho��ed an a�-erage removal from 83-91% for TSS wzith influents ranging from ?1 to 320 mg/L, 82-84% for total copper with influents ranging from 0.94 to 2.3 mg/L, and 50-61% for orthophosphate with influents ranging from 2.46 to 14.37 mg/L. 2. Filterra"�conducted permeabilih� tests on the soil nledia. 7 3. Lab scale testing using Sil-Co-Sil 106 sho��ed percent removals ranging from 70.1% to ' 95.5% with a median percent removal of 90.7%, for influent concentrations ranging from ' 8.3 to 260 mg/L. Filterra�'ran these laboratory tests at an infiltration rate of 50 in/hr. ', 4. Supplemental lab testing conducted in September 2009 using Sil-Co-Sil 106 showed an average percent removal of 90.6°/o. These laboratory tests were run at infiltration rates ranging from 25 to 150 in/hr for influent concentrations ranging from 41.6 to 252.5 mg/1. Regression analysis results indicate that the Filterra� system's TSS removal performance is independent of influent concentration in the concentration rage evaluated at hydraulic loading rates of up to 150 in/hr. Contact Information: Applicant: Sean Darcy ' Contech Engineered Solutions, LLC. ' 11815 Glenn Widing Dr Portland, OR 97220 (503)258-3105 darcvs�ci.conteches.com Applicant's Website: http:/h��.conteches.com Ecology web link: http:��«��v.ecv.��a.go��pro��rams/w�q/stortn��ater/ne��tecl�/index.html Ecology: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360)407-6444 douglas.ho�i-ie(�z;ec�-.wa.gov 8 I, � Date Revision December 2009 GULD for Basic, Enhanced, and Oil granted, CULD for Phosphorus , September 2011 Extended CULD for Phosphorus Treatment September 2012 Revised design storm discussion, added Shallow System. January 2013 Revised format to match Ecology standards, changed Filterra contact information February 2013 Added FTIB-P system March 2013 Added FTIB-C system April 2013 Modified requirements for identifying appropriate size of unit June 2013 Modified description of FTIB-C alternate configuration March 2014 GULD awarded for Phosphorus Treatment. GULD updated for a higher ' flow-rate for Basic Treatment. , June 2014 Revised sizing calculation methods � March 2015 Revised Contact Information June 2015 CULD for Basic and Enhanced at 100 in/hr infiltration rate I � ; i �� 1 �� 1 9 I�- - Operation & Maintenance (OM� Nla n ua I v01 � i . 0 Bioretention Systems C=:::NTECH� ENGINEERED SOLUTIONS i� �-�� , � �� ', � �� 1 effd E!�'�tP�l}10`I �)'S1P.I�'S Table of Contents Overview • Filterra� General Description • Filterra� Schematic • Basic Operations • Design Maintenance • Maintenance Ov� � : I » Why Maintain� » When to Maintc: • Exclusion of Services • Maintenance Visit Summary • Maintenance Tools, Safety Equipment and Supplies • Maintenance Visit Procedure • Maintenance Checklist C=::=NTECH� ENGINEERED SOLUTIONS www.ContechES.com/filterra � 800-338-1122 General Description The following general specifications descibe the gene�al oper��f:ors anc i��airtenance requi��en-,ents t`o� tne Con'ech Engineered Solutions LLC stormwater bioretention filtration system, the Filterra"'. The system utilizes physical, chemicai and biological mechanisms of a soil, plant and microbe complex to remove pollutants typically found in urban stormw�ter runofF. The treatment system is a fully equipped, pre-constructed drop-in place unit designed for applications in the urban landscape to treat contaminated runeff. Bi�st�tEQn P1�nti5oiC;h4,cr�be Co;npir�x Removes Pol�atancs,T55. � Phosphprus.Nitraqen,Rarteria, � � Heavy Mketals.Hydro€�rbans,etc ,� ` _ s ' � . �� •�.° '; 4�, � �� '� � ' �'�r•' a '.f. ��"� NewofExisting � :, � � 4� �� f� T *� ;,i r,t 1 3:,r.l i�.. CdtSh 6asin. � ' ` �� ,r�igher�#evauon Cu+b Cut oi �_ '�� Other Means of � _._ � � +n,+�+Bypass fl�v�r t�ne � �,�, � Clvrrflntv Rt�lief �r � , � }! /�` . � � 4 � �lean G:�t '� ` .. , . . ,. �, r_, � - , — s �. .-.�� "��iN�NM�i� � ::.- ... ,,. _ . � .. __, _ .. - n..�u._.,�..,,�.,., � � <� . . . „ . � � , . � . , - � _ `�•P s�r.� '�� ' '_ __ , ; -►,s+�.r.,r `. . , „ „ .. . . .- # a 1 f. -.n_ � _ ��' i 4- _ _ ., � :. , . ..� . t, � ..�+ �.�'. — _ . . t . ,�.�fr. � 3 ,- . � "' � _ }X�l "_ —" +2'r � _• '�" r., -,:,. . - .. . , � :,: -, ..�. �� .> ;:s � . . . . .._...� . * % — �� §�.:.� . �f �.�..s, ..� .-. r -� .�.- , . < . �. r ... . ... � -t'"_ L .�----.- ' . Stormwater flows through a specially designed filter media mixture contained in a landscaped concrete container. The mixture immobilizes pollutants which are then decomposed, volatilized and incorporated into the biomass of the Filterra`' system's micro/macro fauna and flora. Stormwater runoff flows through the media and into an underdrain system at the ' bottom of the container, where the treated water is discharged. Higher flows bypass the Filterra� to a downstream inlet or outfall. Maintenance is a simple, inexpensive and safe operation that does not require confined space access, pumping or ', ' vacu�m equipment or specialized tools. Properly trained landscape personnel can effectively maintain Filterra'` Stormwater '_ systems by following instructions in this manual. ..;n��.CcntechES.�.��-�;t" �'�.,1 '' 800 .�3�-1 1?2 L Basic Operations • A�oid more ccstly media repiacement. FilterraOO is a bioretention system in a concrete box. • Help reduce pollutant loads leaving your property. Contaminated stormwater runoff enters the filter box through the curb inlet spreading over the 3-inch (ayer of mulch on the Simple maintenance of the FilterraOO is required to centinue surface of the filter media. As the water passes through the effective pollutant removal from stormwater runoff before � mulch layer, most of the larger sediment particles and heavy discharge into downstream waters. This procedure will also metals are removed through sedimentation and chemical extend the longevity of the living biofilter system. The unit �vil� reactions with the organic material in the mulch. Water passes recycle and accumulate pollutants within the biomass, but through the soil media where the finer particles are removed is also subjected to other materials entering the throat. This and other chemical reactions take place to immobilize and may include trash, silt and leaves etc. which will be contained I capture pollutants in the soil media. The cleansed water within the void below the top grate and above the mulch �! passes into an underdrain and flows to a pipe system or layer. Too much silt may inhibit the Filterra'sOO flow rate, I other appropriate discharge point. Once the pollutants are which is the reason for site stabilization before activation. in the soil, the bacteria begin to break down and metabolize Regular replacement of the mulch stops accumulation of such the materials and the plants begin to uptake and metabolize sediment. the pollutants. Some pollutants such as heavy metals, which �yhen to Maintain? are chemically bound to organic particles in the mulch, are released over time as the organic matter decomposes to Contech includes a 1-year maintenance plan with each release the metals to the feeder roots of the plants and the system purchase. Annual included maintenance consists of a cells of the bacteria in the soil where they remain and are maximum of two (2� scheduled visits. Additional maintenance recycled. Other pollutants such as phosphorus are chemically may be necessary depending on sediment and trash loading bound to the soil particles and released slowly back to the (by Owner or at additional costj. The starf of the maintenance plants and bacteria and used in their metabolic processes. plan begins when the system is activated for full operation. Nitrogen goes through a very complex variety of biochemical Full operation is defined as the unit installed, curb and gutter processes where it can ultimately end up in the plant/bacteria and transitions in place and activation (by Supplier) when biomass, turned to nitrogen gas or dissolves back into the mulch and plant are added and temporary throat protection water column as nitrates depending on soil temperature, pH removed. and the availability of o5cygen. The pollutants ultimately are Activation cannot be carried out until the site is fully stabilized retained in the mulch, soil and biomass with some passing out (full landscaping, grass cover, final paving and street sweeping of the system into the air or back into the water. completed). Maintenance visits are scheduled seasonally; the Design and Installation spring visit aims to clean up after winter (oads including salts and sands while the fall visit helps the system by removing Each project presents different scopes for the use of excessive leaf litter. FilterraOO systems. To ensure the safe and specified function of the stormwater BMP, Contech reviews each application It has been found that in regions which receive between 30-50 before supply. Information and help may be provided to inches of annual rainfall, (2) 1wo visits are generally required; the design engineer during the planning process. Correct regions with less rainfall often only require (1) one visit per FilterraOO box sizing (by rainfall region) is essential to predict pnnum. Varying land uses can affect maintenance frequency; pollutant removal rates for a given area. The engineer shall e.g. some fast food restaurants require more frequent trash submit calculations for approval by the local jurisdiction. removal. Contributing drainage areas which are subject to new The contractor is responsible for the correct installation of development wherein the recommended erosion and sediment Filterra units as shown in approved plans. A comprehensive control measures have not been implemented may require installation manual is available at www.conteches.com. additional maintenance visits. Maintenanee Some sites may be subjected to extreme sediment or trash (oads, requiring more frequent maintenance visits. This is the Why Maintain? reason for detailed notes of maintenance actions per unit, helping the Supplier and Owner predict future maintenance All stormwater treatment systems require maintenance for frequencies, reflecting individual site conditions. effective operation. This necessity is often incorporated in your property's permitting process as a legally binding BMP Owners must promptly notify the (maintenance) Supplier of m�intenance agreement. any damage to the plant(s), which constitute(s� an integrol part of the bioretention technology. Owners should also advise • Avoid legal challenges from your jurisdiction's other landscape or maintenance contractors to leave al) maintenance enforcement program. maintenance to the Supplier (i.e. no pruning or fertilizing). • Prolcr,� the expected 'ifes��an of yaur Fi`terra me��a, ..:.��v.C:�rtechES.ccr,:.= lt�rr.:� ' 800-338-1 1�2 Exclusion of Services It is the responsibility of the owner to provide adeqcate irr igaticn �vhen necessary to the plant cf the Filte;ra H system. Clean up due to major contamination s�ch as oils, chemicals, toxic spills, etc. will result in additional costs and are noT covered under the Supplier maintenance contrad. Should a major contamination event occur the Owner must block of� tf,e outlet pipe of the FilterraOO (where the cleaned runoff drGins to, such as drop �nlet) and block off the throat of the Fil�=rra �'. The Supplier should be informed immediately. Maintenance Visit Summary Each maintenance visit consists of the following simple tasks (detailed instruciions belo�vl. l. Inspection of FilterraOO and surrounding area 2. Removal of tree grate and erosion control ,tone� 3. Removal of debris � ,. � . " �_ '�� 4. Mulch replacemer- 5. Plant health evalu��_:" �� b. Clean area around F 7. Complete paperwork Maintenance �oais, �afety �qu�pmer�t anc� �upp�ies Ideal tools include: camera, bucket, shovel, broom, pruners, hoe/rake, and tape measure. Ap, Equipment (PPE) should be used in accordance with local or company procedures. This may include impervious gloves where the type of trash is unknown, high visibility clothing and barricades when working in close proximity to traffic an�: also safety hats and shoes. A T-Bar or crowbar should be used for moving the tree grates (up to 170 Ibs ea.). Most visi' require minor trash removal and a full replacement of mulch. See below for actual number of bagged mulch that is required in each unit size. Mulch should be a double shredded, hardwood variety; do n,-� , . : ! 5 . ,__.. . . :,, ., F i., - . � � �, � �.��- , �- c , .. - . - . - . . :. - . :. . - - - - - _. :.. , „ �. 2 - ---- _- ---- --- -- ---_--- - 6 4 24 6 3 8 4 32 8 4 6 6 36 9 5 8 6 48 12 6 � 10 6 60 15 8 12 6 72 18 9 13 7 91 23 12 ...;.0 �:•,ES __ +, �_ -i Ci �,`�,�._' 1_�? Maintenance Visit Procedure Keep sufficient documentation of maintenance actions to predict locatior soecific maintenance frequencies and needs. An example Maintenance Repoit is �ncluded in this manual. 1. Inspection ot Filterra0 ond surrounding area _' ' " � ``` �'' ` " ' ` ` ` '" ' • Record individual unit before maintenance with photograph (numbered). Record on Maintenance Report (see example in this documentj the � ��; ' , . following: ��=;_ ' � � � x , , �_ ". ..:� � f � ��..� . .g ,_ � �+ _�;.�,o � � � -� ,y' Record on Maintenance Report the following: " �-� - "- � Standing Water yes � no � .-. _ '� Damage to Box Structure yes � no Damage to Grate yes � no �� Is Bypass Clear yes � no If yes answered to any of these observations, record with close-up photograph (numbered). �} .: � , � +h.'a� . 3 ;.� m _ ..... �� - .� � 2. Removal of tree grate and erosion control stones �` ` • Remove cast iron grates for access into FilterraOO box. , ��, . ° -� �. �'- � ��-- . • Dig out silt (if any) and mulch and remove trash & foreign items. �°`�¢ �. � � '` � �• t =.�;�,� Record on Maintenance Report the following: ��_ Silt/Clay yes � no *� Cups/ Bags yes � no Leaves yes ( no # of Buckets Removed 3. Removal of debris, trash and mulch � , • After removal of mulch and debris, measure distance from the top of �3 �� ,.,,... .} � the FilterraOO engineered media soil to the bottom of the top slab. If this -`� � � � ' distance is greater than 12", add FilterraOO media (not top soi) or other) to . ��'� - �� recharge to a 9" distance s ��r� . �"�� _ ��,�_ . - ➢, � Record on Maintenance Report the following: ,� � ,� �� Distance of Bottom of Top Slab (inches) # of Buckets of Media Added � ``�'_ • �tyY =,,� .•:�vv�.Co-�'�chES.con�,%'i'ter:o ' 800-338-1122 _ , � 4. Mulch replacement ; e '''' � �, �` . `�1.jt�y+..:;,,�, • Please see mulch specifications. .,�: "°�-i`� ��i''' • Add double shredded mulch evenly across the entire unit to a depth of 3". �� ~� `� • Ensure correct repositioning of erosion control stones by the Filterra0 inlet .r •. - `=�f �� to allow for entry of trash during a storm event. `�k �. _:�: . i� -� • Rep lace Fi l terra O O gra tes corre c t ly using appropria te Ii Ring or moving too ls, , � � . �, -_ taking care not to damage the plant. �� ' � #:�- � -<�, ��.' �� 5. Plant health evaluation and pruning or replacement `� ` � ` � � as necessary �� '� • Examme the plant's health and replace if dead. � . � • Pr n n t n r r wth in th rr t ir .� � u e as ecessary o e cou age g o e co ec d ections ' • � °�'� Record on Maintenance Report the following: � , � ,,� �5 . � $, +� � . - '' ` �` � -' , � Height above Grate (ft) �. �e , i �`<'�► ' " �� f Width at Widest Point (ft) �? � :'� � Health afive � dead `-+.,. +± � � � �. �.; � > Damage to Plant yes ( no �f� {-��! -,.• _�� Plant Replaced yes � no �_ � . �': '�_� �,�� .,, ,. : ' ' _.�: "'�~ � ,§ T- - '� 6. Clean area around Filterra0 ` �� • Clean area around unit and remove all refuse to be disposed of . ,,, ._,: . appropriately. �...y 4••, " ':�,� -. �;.�,�,t � . a,��.,_� . ' -� 1 f� 'dr','� 1 3-; - � ::_�,� }'..� ..'�' .��at C,„�+�� ..ti. �' .�.: -� '._ � � {r *�s�= 7. Complete paperwork *; ,��.�' }. � '� � { � - - ��.�� • Deliver Maintenance Repori and photographs to appropriate location � ��a"��; ;Y.w'�.�� (normally Contech during maintenance contract period). .'�€s Y T� �'i.� f - ,,�.»�--�:°� • Some jurisdictions may require submission of mamtenance reports in � � �"�� accordance with approvals. It is the responsibility of the Owner to comply :�:ith local regulations. '��:_'_ .r,' ..e�' � � � l� j � �., www.ContechES.comlfilterra � 800-338-1122 Maintenance Checklist . . .. � - - .. - . . . . - . . . . . . . . - - - In er sr�ou'',:_i ;�e fiee ct Excessive Accumulated sediments obstructions allowing free Sediments and/or trash � Inlet sediment or trash or trash impair free flow distributed flow of water should be removed. accumulation. of water into Filterra. into Filterra. Trash and debris should Trash and Excessive trash and/or Minimal trash or other be removed and mulch Mulch Cover floatable debris debris accumulation. debris on mulch cover. cover raked level. Ensure accumulation. bark nugget mulch is not used. "Ponding" in unit could "Ponding" of be indicative of clogging Stormwater should drain Recommend contact Mulch Cover water on mulch due to excessive fine freely and evenly through manufacturer and cover. sediment accumulation mulch cover. replace mulch as a or spill of petroleum oils. minimum. Soil/mulch too wet, Plants not evidence of spill. Plants should be healthy Contact manufacturer Vegetation growing or in Incorrect plant selection. poor condition. Pest infestation. and pest free. for advice. Vandalism to plants. Plants should be Trim/prune plants in Plant growth appropriate to the accordance with typical Vegetation excessive. species and location of landscaping and safety i Filterra. needs. ' Cracks wider than 1/2 � Structure has inch or evidence of soil Structure visible cracks. particles entering the Vault should be repaired. structure through the cracks. Maintenonce is ideally to be performed twice annually. C=::,NTECH� ENGINEERED SOLUTIONS G 2015 Contech Engineered Solutions LLC Revised 6/22/2015 www.ContechES.com/filterra � 800-338-1 122 PUk3LIC WORI<S DEPARTMENT � ,��_�>�,� , , . _ -�----�'�j� ,,`��l`%��:(�;i��l �� s�� M E M O R A N D U M DATE: June 26, 2014 TO: Steve Lee, Devclopment Engineering Mana�er FROM: �,�d---�Ron Straka, Surface Water Utility Engineering Managcr, x7248 U STAFF CONTACT: Hebe C. Bernardo, Surface Water Utflity Engineer, x7264 SUBJECT: Blanket Adjustment—Americast Filterra° The City of Renton Surface Water Utility has issued a blanket adjustment allowing private developments to use Fifterra Systems on private property to mitigate for water quaiity treatment and/or oil control requirements, in accordance with City adopted 2009 King County Surface Water Design Manual and associated City Amendments. The Washington State Department of Ecology has approved the Filterra� Bioretention Systems for General Use Level Designation for Total Suspended Solids, oil and grease, and enhanced dissolved metals treatment. The Americast Filterra� Bioretention Systems for Basic Treatment, Enl�anced Basic Water Quality and/or Oil Treatment will be approved if the following conditions are rT�et: 1. Filterra'� is to be used only on com�nercial and/or industria! site developments where the system will be located in private property. The property owner is responsible for the maintenance and operation of the Filterra°Systems. Ther�> must be a single property owner resp�nsible for maintenar�ce of the Filterra Syste m s. 2. Tfl@ Fl�t@t"t'a'� tl'�atCT12C1� fdCl�lt�/ Srla�� nt,f IJt' ��t';1*£2t� �L�It�ljl'� (.jt�/ �'�J[lt nt �;,,��,�' t�r� any easements dedicated to the City. 3. Each Filterra� unit shall be sized fo►- �;; .;� , ;..�, �.:�;�� :i��, � ,�::,� conductivifiy of 35.46 inches/hour(assuming a hydraulic gradient of 1. inch/inch as listed in the Washington State Department of Ecology Ge� Level Designation for Americast's Filterram) using the sand filter module in tf� latest version of the Western Washington Hydrology Model (WWHM) or otl� Ecology-approved continuous runoff model. The model must indicate the unit is capable of processing 91 percent of the influent runoff file. Mr.Lee Page 2 of 3 June 2G,2014 4. Each Filterra� unit shall be sized for Enhanced Treatment using a filter hydraulic conductivity of 24,82 inches/hour(assuming a hydraulic gradient of 1.41 inch/inch as listed in the Ecology Genera) Use Level Designation) using the sand filter module in the latest version of the WWHM or other Ecology-approved continuous runoff model. The model must indicate the unit is capable of processing 91 percent of the influent runoff file. 5. Each Filterra° unit shall be sized for Basic Treatment using a filter hydraulic conductivity of 35.46 inches/hour(assuming a hydraulic gradient of 1.41 insh/inch as listed in the 1"echnical Information Report (TIR)) using the sand filter module in the latest version of the Western Washington Hydrology Model or other Ecology-approved continuous runoff model. The model must indicate the unit is capable of processing 91 percent of the infiuent runoff file. 6. The use of the Filterra� Bioretention Systems to comply with the Oil Control (Special Requirement#5y requirement for a High Use Site, in addition fio , Enhanced Basic Water Quality Treatment, is also approved. The same Filfierra� unit can be used for both Enhanced Treatment and Oil Control, provided it is sized as specified above. I � - 7. Each site plan must undergo Filterra° review before the unit can be approved for site installation. This will ensure that site grading and slope are appropriate for use af a Filterram unit. 8. Filterra� media shall conform to the specifications subrnitted to and approved by Ecology. 9. Facility inspection, maintenance, and reporting are required by the City of Renton Surface Water Utility per the Ecology National Pol(utant Discharge Elimination System Phase li Municipal Stormwater Permit (Section S5.C,4.c.iii). Facility owners are responsible for ensuring that stormwater facilities are properly maintained and functioning as designed and permitted. The Filterra� facility shall be inspected every six months by the supplier during the first year of operation as offered with the purchase of the Fiiterra� systems. Inspections will be used to determine the site-specific maintenance schedules and requirements. Maintenance of the facility shafl include removing trash, degraded mulch, and accumulated debris from the filter surface and replacing the mulch layer. Maintenance procedures should follow those given in the most recent version o` the Filterra� Bioretention Systems Operation and Maintenance Manual. Dur-ir� the first year of operation of the facifity, written records of the inspections ar maintenance shall be subt��itted to the City of Renton Surface W�tPr UtilitY; the attention of Fdward M�ilhern, Surface Water tJtility En�ine Mr. Lee Poge 3 of 3 � June 26,20'14 10. Following the first year of operation, the property owner or o�vner of tf�e facility shail annually have the Filterra° Bioretention Systems inspected and maintained per the procedures in the most recent version of the Fiiterra� Bioretention Systems Operation and Maintenance Manual. Written records of the inspection and maintenance shall be submitted to the City of Renton Surface Water Uti(ity, to the attention of Edward Mulhern, Surface Water Utility Engineer. If more frequent inspection and maintenance of the Filterra� Bioretention Systems is required by the manufacturer or is needed to ensure performance of the facility, then the additional inspection and maintenance reports completed within the year shall be provided with the annual report. 11. The plans and TIR for the project must be revised to include the use of the Filterra� Bioretention Systems and this adjustment approval. This adjustment is a conceptual approval for using the Filterra� Biaretention Systems for Enhanced Basic Water Quality and Oil Control (Oil Treatment). Further analysis and design ,, calculations shall be included in the TIR for final approval, I 12. The applicant will need to submit a Drainage Facility Covenant for inspection and I maintenance of the Filterra�treatment facility. The Drainage Facility Covenant I can be found in Reference J of the City of Renton Amendments to the 2Q09 King County Surface Water Design Manual. A site plan showing the location of the treatment facility must be included as Exhibit A with the declaration of covenant. 13. The approval of this adjustment does not relieve the applicant fram other city, state, or federaf requirements. Please notify the appficant of our approvaE of the adjustment request and associated conditions related to the approval listed above. If you have any questions about this adjustment, please contact me or Hebe Bernardo. cc; Lys Hornsby,P.E.,Utility Systems Director H:\File Sys\SWP-Surface Water Projects\SWP-27-Surface Water Projects(CIP)\27-3129 Renton Stormwater Manual\ADJUSTMENTS\Blanket Adjustments�2014-06-25-Blanket Adjustment-Filterra-F.doc\HCBah �.0 CONVEYANCE SYSTENI ANALYSIS AND DESIGN I Stormwater runoff generated from the proposed access roadway and a portion of the residential � lots will be collected in a series of catch basins and pipes that will connect to the detention tank. � The conveyance system analysis and design was performed using the rational method. The I calculations are included in this section. � The minimum pipe slope per tl�e Cit�� of Renton requirements is 0.� percent. 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"' ..��as,• . �. . :., .v � � . . ..:., o-. '" .. " - .� �a– '- �".'9 — aa �—— r" �� '___. ..__ _ Information TeChnology -GIS This map is a user generated static output from an Internet mapping site and is for reference only Data layers that appear on this map may or may not be Cl�Of 256 � �2$ 256 Feet RentonMapSupport@Rentonwa.gov accurate current. or otherwise reliable — ��-/`' WGS_1984_Web_Mercator_Auxiliary_Sphere 10/15/2015 THIS MAP IS NOT TO BE USED FOR NAVIGATION Finance & IT Division i � i i i � � � i � i i � CONVEYANCE CALCULATIONS � � � � ( ! � � � � � � 6.0 SPECIAL REPORTS AND STUDIES • Geotechnical Report, prepared by Associated Earth Sciences, Inc, dated June 20, 2013. • Wetland/Stream Study, prepared by Altmann Oliver Associates, dated May ?7, 2008. � Associated Earth Sciences, Inc. . �� '� �� - � � Ser��ing t�e Pacific Nort��vest Since 1��8i � June 20, 2013 Project No. KE130301A Richmond American Homes of Washin�ton 310 29`'' Street NE, Suite 200 Puyallup, Washington 98372 atteirtion: Ms. Jessica Estrada Subject: Preliminary Geotechnical Engineering Stud57 Chelan Creek PUD 922 Chelan Avenue NE Renton, `�'ashington Dear Ms. Estrada: � Associated Earth Sciences, Inc. (AESI} is pleased to present our preliminary geotechnical engineering study for the Chelan Creek PUD site located in Renton, Washington (Figure 1). This study has been prepared for the exclusive use of Richmond American Homes of Washington (Richmond American Homes), and their agents, for specific application to this project. Within the limitations of scope and schedule, our services have been performed i�l ' accordance with generally accepted geotechnical engineering practices in effect in this area at '_ ' the time our study was prepared. No other warranty, express or implied, is made. Ou I observations, findings, and opinions are a means to identify and reduce the inherent risks t� i i_ INTRODti CTION We understand that Richmond American Homes is currently in the feasibility stage of purchasing the parcel with the intent of constructing single-family homes on 16 lots. We anticipate that the homes would be of wood-frame construction and would utilize conventional foundations with relatively light loading conditions. I � Kirkland ■ Everett ■ Tacoma 425-827-7701 425-259-0522 253-722-2992 w«�w.aesgeo.com Gielan Creek PUD I Renton, Washingto�t Prelimi�tary Geoteclanical Engineering Study ; The primary purpose of this study was to evaluate foundation bearing soil conditions. As such, AESI completed a series of exploration pits at the site using a track-mounted excavator i subcontracted to AESI. Our current work included use of this subsurface information to evaluate the thickness and quality of the subsurface sediments. Our work has also included a site reconnaissance as the basis of our current study. Preparation of a Phase I Environmental Site Assessment (ESA) for this property by AESI is being prepared concurrently with this ' study. LITERATURE REVIEW I' The following applicable plans were reviewed as part of our study. These documents were 'I provided for our use by CES Northwest, Inc. and made available to AESI through their ', technical document FTP web site. Recorded lat lans: Chelan Creek PUD Parcel Ma b Cramer Northwest Inc., I P P P Y dated June 20, 2008 � No prior geotechnical design reports were available for review at the time of AESI's limited geotechnical study. SITE DESCRIPTION The Chelan Creek property (Parcel Nos. 1Q2305-9106 and 102305-9440) is located at the southerly terminus of Chelan- Avenue NE and encompasses approximately 4.49 acres (Figure 2). The property is generally rectangular in shape and is bordered on the north, south, and west by existing residential development and on the east by Duvall Avenue NE. The site is currently accessed via a paved driveway extending south from NE 10`'' Street on the northwestern corner of the praperty. There is an existing structure on the north end in the vicinity of Lot 15, and there was a residence on the southern portion of the lot on Lot 7 that has been demolished. An existing well was observed immediately south of the detached garage in the northern end of the property. It is our understanding that Chelan Avenue NE will exist down the west side of the project area for access to the southern lots. , There is a wetland that traverses the site from the southwest corner to the northeast corner of the site. The wetland se arates h ite into w r t e s t o a eas with Lots 1 throu h 4 loc p g ated at the southeast corner of the property. These lots will be accessed from the south via an extension of Chelan Place NE. i June 20, 2013 ASSOCIATED EARTH SCIENCES, INC. , MM/!d-KEI30301A2-Projecu{201303011KEIWP page 2 �_ Giela�i Creek PUD � Renton, Waslzington Prelirninary Geotedinical Engineering Study Site elevations range from approximately 412 feet in the southwest corner of the site to a high of approximately 434 feet in the northeastern corner. The topography of the site generally ''� slopes gradually down to the southwest. The two proposed development areas slope slightly ; down to the center toward the wetland that traverses the site. As noted previously, the proposed project would include construction of single-family homes on 16 lots. Access to the lots would be provided by new roadways constructed on the property connecting the south end of Chelan Avenue NE, and the north end of Chelan Place NE. Site grading, the Iot and road layouts, and the approximate locations of the explorations conducted for this study are included in the "Site and Exploration Plan," Figure 2. SUBSURFACE EXPLORATION AESI excavated a total of six exploration pits across the property on June 15, 2013. The � approximate locations of the pits are shown on the "Site and Exploration Plan," Figure 2. The pits were excavated using a track-mounted excavator and conditions in the pits were � documented by an engineering geologist from our firm. Summary descriptions of the soil and I ground water conditions encountered at the site are provided below. Detailed descriptions of the sediments encountered in each exploration pit are provided on the exploration logs included in Appendix A. Topsoil Topsoil sediment units were encountered in all of AESI's exploration pits ranging in thickness ' generally from 6 to 12 inches. In general, the topsoil consists of a very loose, dark brown, seasonally wet mixture of silt and sand with variable amounts of organics, and few amounts of gravel. These loose to very loose, organic soils are not suitable for direct foundation support. It is our opinion these loose soils should be removed during mass excavation of the site. Fill Fill soils were encountered in EP-3 and EP-4 located on Lot 7 and a portion of Lot 8. The fill material appears to be associated with the demolition of the residence that was in the vicinity. The fill extended to a depth of about 6 feet and consisted of loose sands with variable amounts of crushed concrete and brick. The fill is not considered suitable for support of the new house foundations. June 20, 2013 ASSOCIATED EARTH SCIENCES, INC. MM/!d-KE130301A2-Projecls1201303011KE1iVP Page 3 Chelmi Creek PUD Re�tton, Washi►tgtort Prelimi�tary Geotechnical Erigineering Study Vashon Recessional Outwash Vashon recessional outwash was encountered in all the pits with the exception of EP-3 and EP-4 and generally consisted of inedium dense, moist sand with variable gravel contents and trace to few amounts of silt. The unit was light brown to red-brown due to natural weathering and iron-oxide staining. We interpret these sediments to be representative of Vashon recessional outwash. The Vashon recessional outwash was deposited by meltwater streams that emanated from the retreating glacial ice during the latter portion of the Vashon Stade of the Fraser Glaciation approximately 13,000 years ago. Where encountered, the Vashon recessional outwash sediments extended to a depth of approximately 2.5 to 3 feet. Recessional outwash soil, as encountered and described herein, is considered suitable for support of residential structures. Due to the coarse grain size and low silt contents of these soils, localized ground water can be present depending on the time of the year and should be anticipated in any deeper construction excavations. Vashon Lodgement Till �, Natural sediments encountered directly below the recessional outwash and below the fill described above in all of AESPs exploration pits generally consisted of dense to very dense, ;, unsorted sand with little amounts of silt, few ranging to little amounts of fine to coarse gravel �, and trace amounts of cobbles. We interpret these sediments to be representative of Vashon lodgement till. The Vashon lodgement till was deposited directly from basal, debris-laden glacial ice during the Vashon Stade of the Fraser Glaciation, approximately 12,500 to 15,000 years ago. At a few of these locations (EP-2, EP-3, and EP-4), the density of the upper portion of the till was observed to be medium dense. The reduced density present in the upper portion of the till at these Iocations, below the completely weathered till described above, is interpreted to be due to a lesser degree of weathering. The Vashon lodgement till extended beyond the maximum depths excavated in all the exploration pits. Undisturbed medium dense to very dense lodgement till sediments are suitable for foundation support. The elevated silt content of this unit makes it sensitive to moisture and disturbance, so the foundation subgrade should be protected, as necessary. Geologic Mapping Review of the regional geologic map titled Geologic Map of the Renton Quadrangle, King Counties, by D.R. Mullineaux (1965) indicates that the project area is underlain by Vashon lodgement till. Our interpretation of the sediments encountered in our exploration pits is in general agreement with the regional geologic mapping. Jinte 20, 2013 ASSOCIATED EARTH SCIENCES, INC. ,Nbt/!d-KE130301A2-Projects1201303011KElWP Page 4 Chelan Creek PUD Rentora, Washington Preliminary GeoFeclrnical Eri2ineering Study Ground Water No ground water or seepage was encountered in any of the explorations pits. However, ground water may be present across the site during wetter periods of the year. Ground water in areas containing till soils shallow below the ground surface typically occurs as interflo��. Interflow occurs atop lodgement till or other relatively impermeable sediments. Interflo« generally occurs during the months of October through June when surface water infiltrate�; down through a relatively permeable overlying soil layer and becomes trapped atop a very lo« permeability, parent sediment (usually lodgement till). Potential interflow would follow th� topography and likely flow in the direction to��ard tlle �vetIa�ld at ttic eei�ter of the site a��,�av from the topographic highs describe�i pr��iously. CO'�CLL:SIONS A�D REC01��11��1E;VDaTIOI�S The medium dense to dense natural sediments encountered in aur exploration pits are generally suitable for foundation support. The upper, loose, soil horizons (including topsoil) and existing fill are not suitable for foundation support. The following sections provide our recommendations for foundation support and support of slab-on-grade floors. Site Preparation Site preparation should include removal of all foundations, existing buried utilities that are not to remain in service, landscaping, and any other surficial deleterious material that is not part of the planned project. Additionally, any upper organic topsoil encountered should be removed and the remaining roots grubbed. Areas where loose surficial soils exist due to grubbing operations should be considered as fill to the depth of disturbance and treated as subsequently recommended for structural fill placer�ient. Once any demolition and stripping ha��e been completed, e�isting surficial loose sediments and existing fill should be addressed. The underlying materials should be compacted to a firm and unyielding condition, as determined by an on-site AESI representative. Any soft or yielding areas may require further removal or other measures to provide a more stable surface for fill placement. Structural fill should then be placed to reach desired subgrade elevation. Areas of slab-on-grade floars may be supported by re-compacting the exposed existing fill subgrade to a firm, unyielding condition, as determined by an on-site AESI representative. It should be noted that if existing loose sediments or fill are left in place under slabs, some risk of future settlement will result. The recommendations presented here for limited removal and replacement of existing fill are intended to balance up-front costs and long-term risks, and should perform well based on the existing subsurface data. If some increased risk of future June 20, 2013 ASSOC7,4TED EARTH SCIENCES, INC. 1��, t;,�:, ,� _-P; . _ .?�i: . .._ t'P ��e � Clsela�z Creek PUD Rento�a, Washingtort Prelinti�iary Geotechnical Eligineering Study settlement is not acceptable, all existing fill and loose sediments should be removed completely to expose the underlying, medium dense sediments and replaced ��ith structural fill, Foundations I Spread footings may be used for foundation support of the proposed buildings provided they � are founded directly on the competent natural sediments, or on structural fill. The foundation bearing stratum, consisting of inedium dense to very dense Vashon sediments, is relatively ' shallow and spread footings may be used for foundation support. The estimated depth to the foundation bearing stratum at each exploration pit location is sho��n �, in Table 1. Table 1 Estimated Depth to Foundation Bearing Stratum i , Estimated Depth to Bearing Ex loration Pit (feet)�'� EP-1 2 Z EP-2 2 EP-3 6 EP-4 6 � EP-5 2 � EP-6 2 Note 1 - Depths to bearing sediments are approsimate and ma}� var}�at other lo�arions around the property. The fill associated with the former residence on Lot 7 and Lot 8 is anticipated to be present on the properry. These fill soils should be removed and replaced in these areas prior to footing placement. All footing excavations must penetrate to the prescribed bearing strattim. Care should be taken not to allow water to soften the anticipated silty subgrade soils. Structural fill placed below foundation areas, road«�avs, etc. should be placed �� ' ? in the following section of this rep�� For footings founded either dir��.ti a�� :,;��,:�,:�� i��u�u��. u,;�� ,Lr� u�;��;;�, undisturbed, native sediments or structural fill, we recommend that an allowable bearing pressure of 2,000 pounds per square foot (ps� be used for design purposes, including both dead and live loads. An increase of one-third may be used for short-term wind or seismic June 20, 2013 ASSOCIATED EARTH SCIENCES, INC. MM/!d-KE130301A2-Projects1201303011KE1WP Page 6 Chelmz Creek PUD Re�uon, Washington Preliminafy Geotechnical Engineeri�tg Study loading. Specific recommendations regarding placement of structural fill below foundation areas are provided subsequently in this report. Perimeter footings for the proposed buildings should be buried a minimum of 18 inches into the surrounding soil for frost protection. No minimum burial depth is required for interior footings; hawever, all footings must penetrate to the prescribed stratum, and no footings should be founded in or above loose, organic, or existing fill soils. The area bounded by lines extending downward at 1H:1V (Horizontal:Vertical) from any footing must not intersect another footing or intersect a filled area that has not been compacted to at least 95 percent of American Society for Testing and Materials (ASTM):D 1557. In addition, a 1.5H:1V line extending down from any footing must not daylight because sloughing or raveling may eventually undermine the footing. Thus, footings should not be placed near the edges of steps or cuts in the bearing soils. Slab-on-Grade Floor Support Slab-on-grade floors may be constructed either directly on the undisturbed, medium dense to dense, Vashon sediments, or on structural fill placed over these materials. Areas of the slab subgrade that are disturbed (loosened) during construction should be re-compacted to an unyielding condition prior to placing the pea gravel, as described below. In order to control moisture vapor transfer through the slab, slab-on-grade floors should be constructed atop a capillary break consisting of a minimum thickness of 4 inches of washed pea gravel. The pea gravel should be overlain by a 10-mil (minimum thickness) plastic vapor retarder. Structural Fill Struciural fill should consist of inorganic soil, free of deleterious materials, placed in maximum loose lift thicknesses of 8 inches with each lift compacted to at ieast 95 percent of the modified Proctor maximum dry density, as determined by ASTM:D 1557. Structural fill , placed below footing areas should extend laterally beyond the footing edges a distance equal to , or greater than the thickness of the fill. The on-site Vashon sediments that are free of '� deleterious materials are suitable for reuse as structural fill provided they are present at a moisture content suitable for achieving the specified compaction. Use of the on-site Vashon till deposits containing high silt contents as structural fill will likely require some moisture conditioning. Ju�te 20, 2013 ASSOCIATED EARTH SCIENCES, INC. i�Lbfi;�;-K'E130."s01A2-Prnjecrs',?0130�01'hEili�P Pave '] b c;��r�l,� cr��Pc�� Re�iton, ti�as/iiragton Prelimina�y Geotecl�nical E�zgilieeri�tg Stirrll� If fill is placed during wet weather, or if proper compaction cannot be attained, a select import material consisting of a clean, free-draining gravel and/or sand should be used. Free-draining fill consists of non-organic sail with the amount of fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve fraction and at least 25 percent of the material greater than the No. 4 sieve. A representative from our firm shauld observe the stripped subgrade and be pres�nt during placement of structural fill to observe the work and perform a representative number of in-place density tests. In this way, the adequacy of the earthwork may be evaluated as filling progresses and any problem areas may� be corrected at that time. CLOSURE We appreciate the opportunity to be of service to you on this project. Should you have any questions regarding this report or other geotechnical aspects of the project, please call us at your earliest com�enience. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, �'Vashington �1��1� � ,��N,�� t;�;;�';, �� ' ��Fp E=�� ,� .a=:. � � _ � - � cr �- �� , j 9` ''725; � .-� `�/STEF�"a��.��g, L� �,�orvat F` � � '�'��-a-�"F � ! i� Matthew A. 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REDUCE ITS EFFECTIVENESSAND LEADTO INCORRECT INTERPRETATION. Y m � : Associated Earth Sciences,Inc. VICINITY MAP FIGURE 1 U � - CHELAN CREEK PUD DATE 6113 � � � . RENTON, WASHINGTON PROJ.NO. KE130301A �^1�� f L.�F�}!'v 1/A N!,/ IG-},R-'3 �\ �t �ly[�7! w 1 b E lt .�� [�_ ! Ut C !i' S!G C GI flydCfiY L � �+N� ` ^�_ 5.�r!1l1-__ .' •� 1 1' � uy��g �� F ` �' � � -- ,Ae ^.-r un i � Y�I � � I R' `,� � �IE -� !' ..c. u w r o e, t a.r�._. �� . { a 1!` F �� \ ir�v o� r.a �.: . -�' R3 f� n i at�c� .cc+rerF �r ��V� ,3i�d i �n�uT.: � �i - � �i�� .�y�.°J� �`� 1 ¢ . �` ` G •n -� � -.��I .°�il L F I i.?�F � �� 1 't _-.F?�ID.YG-�\ "l�f 1 -w.12.{ ko'� � ��Y I � It. i �� n.-- - �eivais¢c � g r.rr3 ��i � ^5 5 ��.. F.�S�s . rv i�-r.�te �. !Oi r� 8 �1I �� 1\ a< 'n to. �o f ! �'� �,^�a,�? ;��:.st.k aT.. �)�� ('`� :1�� (nyy�,_F�1I�c tnr. �4•'�� 1 � I � �' 'I -1 - � __. �"F�+b _ �i, �.C' ip� ,�� Ov.<4�P. I �/"'"' .x11,y� ' sa� �2� Ls� �IF\ ��.hy (� ��a�f'k�_. 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Y �' { TYP ��_-. � , /' -� ` J wVpr 1, 6T�`a ' w � 1 '� �1 rsa�x �",�= �r-Fz�cl /�sa s�.y � �.''}, � i� �or z �s � V�r�atr� r.�`_-f a""e'j r�'R Fn l/c � siii. �' R��y � � "� A� � 9 in Z �S r r�� yUy�� e � 4 1'�s7zz1£s zr• i x�i+v � �j � 1 ' /� 'C7G7:JiL':tirl: O�y' �• �T �`�� I^ � ;%�, rc q�vv �. GYi c• �bz• f+' � �`� 1.� � ,�n�,,:.�s,r i�-:L 'C� rr.c:h��,v�y.a ; s�� S �� " ;� A�� i�=3: o-_�'v�4 r� ,}7 -'%/'� 6 Li�.c tt Os..l. .:•. J�' 9 � �r.t:��::=�> .. ,n fl� �o:n-r.r��_, HT�t1tt"C��ri. �o.�r. 1�6� i � � ._, - .n , �a � . ,. _ " N �cn;�vt� m 4tih"f.:F,iSI ' � p. .. r A.._.uE11=11 ��J W nL:f�� t .� "'�� '�icu`i.�'c��° / iz c.ts (:�. x le � $� (r.s' ( ��''+�. , � , ��,$ ��s A N � rit Nr .r.r� �� " n.([0 s Ir c I fr F- � �y:�r . �U�ti Oh S r , � Y .f.t LL I.� L"J T .l �S � Z'4 5T�iJ ' I�(�r ,�o [ :-G�l:. [ii.4i 9AIIJ.t !(R"�IT�(, m 4� d PP S( t. [. � 1r� j tf1.r.�1;�1F7 ...�..: �� ,�f� i r u _ �, . I __ _ 0 50 100 � o FEET � REFERENCE: CRAMER NORTHWEST,INC. Y � � Associated Earth Sciences,Inc. SITE AND EXPLORATION PLAN FIGURE 2 � � CHELAN CREEK PUD DATE 6l13 � � � _ RENTON, WASHINGTON PROJ.NO. KE130301A APPENDIX A Exploration Pit Logs ;- ,� , � -�� _, LOG OF EXPLORATiON PlT NO. EP-1 � This log is part of the report prepared by Associated Earth Sciences, Ina (AESI)for the named project and should be � read together with that repor�for complete interpretation.This summary applies only to ihe location of this trench at the m time of excavation.Subsurface conditions may change at this location with the passage of time.The data presented are o a simplfication of actual conditions encountered. DESCRI PTI ON Topsoil Loose, moist, tan to brown, SAND, with silt and organics. �---' i 1 Vashon Recessionai Outwash � Medium dense, moist, tan to brown, sandy SILT,with cobbles. 2 � ti , i � 3 i � Weathered Vashon Lodgement Till 4 i Medium dense, moist, brown grading to gray, sandy SILT, trace cobbles, some iron staining. Vashon Lodgement Till Dense to very dense, moist, gray, sandy SILT, trace cobbles. 5 Bottom of explora#ion pit at depth 5 feet ' ' 6 No seepage. No caving. 7 8 9 10 j 11 ' 12 13 � 14 15 - ' i 16 -� , ; '' 17 i 18 19 i i � o Ghelan Creek PUD N � Renton, WA � a " Associated Earth Sciences Inc. pro ect No. KE130301A � Logged by: MM � 1 0 � � � lyys � � �, Approved by: 6/15/13 a U LOG OF EXPLORATION PIT NO. EP-2 � This log is part of the report prepared by Associated Earth Sciences, Ina (AESI}for the named project and should be L read together with that report for complete interpretation.This summary applies only to the locafion of this trench at the � time of excavation.Subsurface conditions may change at this location w'ith the passage of time.The data presented are ❑ a simplfication of actual conditions encountered. DESCRIPTION Topsoil , Loose, moist, tan to brown, SAND,with silt and organics. - 1 Vashon Recessional Outwash Medium dense, moist,tan to brown, sandy SILT, with cobbles. 2 Weathered Vashon Locigement Till Medium dense, moist, brown grading to gray, sandy SILT, trace cobbles,some iron staining. 3 Vashon Lodgement till 4 Dense to very dense, moist, gray, sandy SILT, trace cobbles. Bottom of exploratlon pit at depth 4 feet 5 No seepage. No caving. 6 7 8 9 10 11 � 12 13 14 , 15 L 16 17 18 � 19 I nn L- � o Chelan Creek PUD N � Renton, WA � a " Associated Earth Sciences, Inc. pro ect No. KE130301A o Logged by: MM � �, Approved by: �� _� .,x � fi/15/13 a � U LOG OF EXPLORATION PIT NO. EP-3 � This log is part of the report prepared by Associated Earth Sciences, lnc. (AESI)for the named project and should be � read together with that report for com�lete interpretation.This summary appiies only to the location of this trench at the � time of excavation.Subsurface condifions may change at this location with the passage of time.The data presented are ❑ a simplfication of actual conditions encountered. DESCRIPTION Topsoil �,Loose, moist, tan to brown, SAND, with siit and organics. � 1 Fill Loose to medium dense, moist, gray, silty SAND, with 2 to 4 inch crushed rock, scattered brick and 2 concrete debris. 3 4 5 6 Vashon Lodgement Till � Dense to very dense, moist, gray, sandy SILT, trace cobbles. s � � Bottom of exploration pit at depth 7 feet ` 8 N�seepage. No caving. � i 9 10 : � 11 � ' 12 i 13 � 14 15 , 16 � 17 18 � � , 19 �i ( ' 'i _ � 'I _ o Chelan Creek PUD ' � N ; ' Renton, WA _ , a " Associated Earth Sciences, Inc. Pro ect No. KE130301A o Logged by: MM 1 � �4�.y � �.�- ,....�6 � � Approved by: �-� � F 6/15113 a r=-. � U LOG OF EXPLORATION PIT NO. EP-4 � This log is part of the report prepared by Associated Earth Sciences,Inc. (AESI)for the named project and should be � read together with that repor�for complete interpretation.This summary applies only to the location of this trench at the m time of excavation.Subsurface condifions may change at this location with the passage of time.The data presented are o a simpification of actual conditions encountered. DESCRIPTION Topsoil Loose, moist, tan to brown, SAND, with silt and organics. � 1 Fill Loose to medium dense, moist, gray, silty SAND,with 2 to 4 inch crushed rock, scattered brick and 2 concrete debris. 3 4 5 6 Vashon Lodgement Till Dense to very dense, moist, gray, sandy SILT, trace cobbles. 7 - -- Bottom ot exploration pit at depth 7 feet 8 No seepage. No caving. f 9 , 10 ; ', 11 I 12 13 14 15 �� 16 17 18 � i � 19 � nn , GV � N Chelan Creek PUD 0 N ' Renton, WA � a " Associated Earth Sciences Inc. Pro ect No. KE130301 A � o Logged by: MM � 1 ! �; Approved by: � � � ,-:�_ � 6/15/13 � U Y LOG OF EXPLORATION PIT NO. EP-5 ' � This log is part of the report prepared by Associated Earth Sciences, Inc.(AESI)for the named project and should be � read together with that report for complete interpretation.This summary applies only to the location of this trench at the � m time of excavation.Subsurface condifions may change at this location with the passage of time.The data presented are ' o a simplfication of actual conditions encountered. DESCRIPTION � � Topsoil , Loose, moist, tan to brown, SAND, with silt and organics. � ' � Vashon Recessional Outwash Medium dense, moist, reddish brown, sandy SILT, with cobbles. 2 - 3 4 � Vashon Lodgement Till 5 Dense to very dense, moist, gray, sandy SILT, trace cobbles. 6 Bottom of exploration pit at depth 5.5 feet No seepage. No caving. ; 7 8 ' 9 10 11 12 13 14 - 15 - 16 17 18 19 nn co o Chelan Creek PUD N ' Renton, WA � a o Associated Earth Sciences, Inc. pro ect No. KE130301A � Logged by: MM 1 �, Approved by: � � � � � 6/15/13 � U Y LOG OF EXPLORATION PIT NO. EP-6 ---- -- --- � This log is part of the report prepared by Associated Earth Sciences, Inc.(AESI)for the named project and should be L read together with that repor�for com�lete interpretation.This summary applies only to the location of this trench at the � time of excavation.Subsurface conditions may change at this location with the passage of time.The data presented are o a simplfication of actual conditions encountered. DESCRIPTiON Topsoil , Loose, moist, tan to brown, SAND, with silt and organics. 1 Vashon Recessional Outwash Medium dense, moist,tan to brown, sandy SILT, with cobbles. 2 3 Weathered Vashon Lodgement Till Medium dense, moist, brown grading to gray, sandy SILT, trace cobbles, some iron staining. Vashon Lodgement Till 4 Dense to very dense, moist, gray, sandy SILT, trace cobbles. 5 Bottom of exploration pit at depth 4.5 feet No seepage. No caving. 6 � � 7 � ; i i 8 9 1Q 11 12 13 14 15 ' 16 i 17 18 � 19 nn GV � N Chelan Creek PUD 0 N ' Renton, WA � a o Associated Earth Sciences, Inc. Pro ect No. KE13U301A o Logged by: MM 1 � � � � � � a Approved by: -� � 6/15/13 � U Y Altma.r�r� (Uliver� Assc.�ciates, I .I_.C� 1'��IS„� : ( .,�i�,:u,�n 11 1 �•;�V 1 ��I�i,� � i_ �i ,.,. �vFy_oph�.�.;r��;n�a �u1� �' II\'ll't)Illlll'I;I:I� �� Q t r (", ' . 5 2008 ��►�,��;; �_ �11N 2 i .,�,��:�:�1�� '��CU' I \i�c iiilt•s��Ill'c �� May 27, 2008 AOA-3601 Linda Pillo 5411 36`� Ave. SE Seattle, WA 98126 SUBJECT: Wetland/Stream Study for Chelan Creek PUD, Renton Parcels 102305-944Q and -9106 Dear Linda: On September 12, 2007 I conducted a wetland reconnaissance on the subject property utilizing the methadology outlined in the 1997 Washington State Wetlands ldent�cation and Delineation Manual. The primary purpose of the reconnaissance was to review the wetland delineation and classification conducted by AlderNW in April of 2007. The wetlands as delineated by AlderNW(Attachment A) and depicted on the survey drawing prepared by Cramer Northwest Inc. appeared accurate. Existing Conditions The no�them and western portions of the site are developed with two single-family residences and associated tawn and omamental areas. The remainder of the site is undevetoped and consisted of a mix af forested areas and blackberry. The wetland delineated by A1derNW is located within a broad topographic swale ihrough the central portion of the site and is associated with a small well-deflned st�eam channel. Vegetation within the wetland and the riparian corridar of the stream included red a{der(Alnus rubra), salmonberry(Rubus spectabilis), Himalayan bladcberry (Rubus discolo�, evergreen blackberry (Rubus laciniatus), creeping buttercup (Ranunculus repens}, and skunk cabbage (Lysichiton amer+canum). The wetland on the site was determined by AlderNW to be a Category 2 wetland and this classfication appears accurate. Category 2 wetlands require a standarcl 50-foot buffer in the Ciiy of Renton. The stream on the property is not mapped on the City of Renton's stream map (Figure 43-050Q4), but drains down irito a mapped Class 4 stream. Class 4 streams in the City of Renton require a standard 35-foot buffer nom � Linda Pillo May 27, 2008 Page 2 the ordinary high water of the stream channel. Although the stream was not delineated by AlderNW, the entire stream buffer would be contained within the ' wetland buffer. , Wetland/Stream Buffer Averaging The project proposes to implemeni a buffer averaging and enhancement pla� , (Drawings W1.1, W2.1� and W3.1). Under this plan, 11,597 s.f, of degraded wetland/stream buffer would be reduced and replaced with 11,865 s.f. of additional buffer. In no case would the buffer be reduced below 25 feet. The proposed buffer reduction area consists primarily of periodically mowed lawn. Since the proposed buffer replacement area is primarily fores#eti there should be a net increase in the overall habitat value of the buffer on the site. Furthermore, due to the degraded condition of the area in the vicinity of the reduced buffer, the area will be planted with a variety of native trees and shrubs to increase the plant species and structural diversity of the buffer adjacent the proposed development. Downed logs and other woody debris will also be placed within the buffer to further increase the habitat value of the area. Implementation of the buffer averaging and enhancement plan should increase the value of the buffer over cunent conditions and shauld meet the buffer averaging criteria outlined in RMC 4-3-050M_6.f. Goal, Objectives, and Performance Standards for Enhancement Area The p�imary goat of the enhancement plan is to increase the value of the buffer over current conditions. To meet this goal, the following objectives and performance standards have been incorporated into the design af the plan: Obiective A: Increase the structural and plant species diversity within the enhancement area. Performance Sfandard: Following every monitoring event for a period of at least five years, fhe enhancement area wrll contain at least ?0 native plant species. !n addition, there will be 10090 survival of all woody p/anted species throughout the enhancement area at the end of the first year of planfing. Fo!lowing Year 1, success will be based on an 8Q'�6 survival rafe or areaJ cover of planted or recolonized na6ve species of 15% at construction approval, 20% after Year 1, 30% affer Year 2, 40% after Year 3, 50% aRer Year 4 and 60� after Year 5. Obiective B: Limit the amount of invasive and exotic species within the enhancement area. Performance Standard:Af�er constnrcfion and fo!lowing every monitoring event for a period of at leasf five years, exotic and invasive plant speciss will be maintained at , levels below 10% tofal cover in all planted areas. These species include, but are not limifed to, Himalayan and evergr�en 6lackberry, reed canarygrass, moming glory, Japanese knotweed, English ivy, thisde, and creeping nightshade. Linda Pillo May 27, 2008 Page 3 Construction Management Prior to commencement of any work in the enhancement area, the clearing limits will be staked and any existing vegetation to be saved will be clearly marked. A pre- construction meeting will be held at the site to review and discuss all aspects of the project with the landscape contractor and the owner. A consultant will supervise plan implementation during construction to ensure that objectives and specifications of ihe enhancement plen are met. Any necessary significant modifications to the design that occur as a result of unforeseen site conditions will be jointly approved by the City of Renton and the consultant prior to their implementation. Monitoring Methodology The monitoring program will be conducted for a periad of five years, with quarte�ly reports during the first year and annual reports for Years 2 through 5. Vegetation sampting plots will be prepared and a record wii! be kept of all pfant species found. Vegetation will be recorded on the basis of relative percent cover of the dominant species within the vegetative strata. Photo-points will be established ftom which photographs will be taken throughout the monitoring period. These photographs wil! document general appearance and p�ogress in plant community establishment in the enhancement area. Review of the photos over time wil) provide a visual representation of success of the enhancement plan. Maintenance Plan Maintenance will be conducted on a routine, year round basis. Additional maintenance needs will be identified and addressed following periodic maintenance reviews. Contingency measures and remedial action on the site shalt be implemented on an as- needed basis at the direction of the consuttant or the owner. Weed Control I Routine removal and control of non-native and other invasive plants (e.g., Himalayan �I and everg�een blackberry, Scot's broom, reed canarygrass, Japanese knotweed, ' English ivy, moming glory, thistle, clematis, and creeping nightshade) shall be performed by manual means whenever possible. Chemical means will only be used if necessary. Undesirable and weedy exotic piant species shall be maintained at levels below 10% tofal cover within any given stratum at any time during the five- year monitoring period. The following outlines treatrnent for specific species. Hlmatayan and Evergreen Btack6erry Contro/ Small patches (a�eas <3' x 3') need to be grubbed out, large areas (>3' x 3') need to be cut down. New shoots (approx. 6" in hei�ht)which reappear should be spot- sprayed with herbicide onty fi necessary and unde�the supenrision of a consultant. � Linda Piilo May 27, 2008 Page 4 General Maintenance Items Routine maintenance of pianted trees shall be performed. Measures include resetting plants to proper grades and upright positions. Tall grasses and other competitive weeds shall be weeded at the base of plants to prevent engulfinent. Weed control should be performed by; hand removal, installation of weed barrier c(oth with mulch rings, or selective weed-whacking. If weed-whacking is performed great care shall be taken to prevent damage to desired native species either planted or re-colonized. Woody plants shall only be pruned at the directian of the c�nsultant or to remove pest infestations. Contingency Plan All dead plants will be replaced with the same species or an approved substitute species that meets the goal of the enhancement plan. Plant material shall meet the same specifications as originally-installed material. Replanting will not occur until after reason for failure has been identified (e.g., moisture regime, poor plant stock, disease, shade/sun conditions, wildlife damage, etc.). Replanting shall be completed under the direction of the consultant, City of Renton, or the owner. As-Bui1t Plan Following completion of construction activities, an as-built plan for the enhancer��ent area will be provided to the City of Renton. The plan will identify and describe any changes in relation to the original approved plan. If you have any questions please call me at (425) 333-4535. Sincerely, ALTMANN OLIVER ASSOCIATES, LLC John Altmann I'! Ecologist , Q � Z W � T V �.Q.. � Q A1derNW Ap� t 9,200� Projed Nv_a4407 N1s. Lir�da P�o 922 Chelaa Ave�e Re�toa, WA 98059 Sabjeck Prel'nminary Sitc Evalaaiiam P'itlo I'rvperty_ • Du�vall Avenne NE at NE 9`�Street �,w� Tax Pamel No's. 1023059440 arni 1023059106 Dea�-I4Is.P�lo: As.reqaes6ed I o�plebaa an evalua�ion af ihe prnpe,�ip ide,adified as K'iqg Coud.y Taa Pat�cel#'s I(32305944U a�d 1Q23059106, m t3�e City af Re�tbo�. Tbe pa�poee af thi.s wosk was t�o oomptele a sme � #a n�Ce a de�atio��if w�etlnnd t�on�itia�s ano p� ou ar �y adjaoa��a t�e pmp�ties. Our scope of work indaded a snde visit on Apr� 8, Z00'!, at wluch timc we oo� aar si�e eval� In �g a�ur �e evaluatia�, we follavQed tLe general prooedutes for t�e s+a�ne o�ite na�ethodology as arttia�ed ia the�ar�d, 199� Wrulilirgtor+ State Wetlands Ida�Aifrca�Ta�r cmd Diel'ureatlar Mmr� 'Tbis pinoodtme im►oh�Es 8�81ysis af veg�tion pat�t�s,soa�l caoodmo�s,aad�r-sarfaoe hydrnlogy iu makigg a�amo�inm�tian a�vvd�aonrd ao�s. 7Le�b.joct P�Y�ffi�Y�i�m�ade Bp af two parods with a combwaed a�ea of appmacimat�ay a acaes. We have id�ified the liomuts o�a wedaad a�a ari�at a calvect draioing aato d�e progerty fmm the�st side of Davall Av+e�ve NE. h�across tl�e psn�iy t,o�uvaid the�co�cr A�a1 stream �s �tbe v�and We Ptaoad 8�ing a�azi�n8 t�ne limits af the wetiaad. Flags aa�Sa�o�t a�ange. Ftags abng the west side oEf ti�e ' we�land aie cou.�xabively m�ed ANW-1 at tl�e cntve�t m l�avail Aveane NE tn ANW-18 almg t6e west pro�aty 1�c n�r the�oa�hwest oomer a�f ti�e pmpa�tp F'I�s on the e�t side c�f t�ee wetlaad a�e rmmbe=�od ANR� 301 at I7uvall A�v�ue tn ANW 118 near tbe gautha�st pt+nQe�tp_oornecr. Tl�e adtad�ed figsie t�i� the a�prauom�Le ex�t of t6e�}m�d on i�e graperty. Tlss a�ap's4 p�6od as ffi aid to po�ur sarwy�s in loca#iag t�e vv�tland� It�my iafiecpretatian a�the City af Rca�rm Cade 8iat�+e�aa the pmperiy maf.a�e cartetia£or� � a City o�ReaUon Ca�go�y 2 W�ad. As a Cst�Cxy 2 wattaod,a 50$bt�S'et is a�a�. in a000rtlaooe aith Reataa Codq new�is limi�od within w�and t�e�abod 6aff�. 1be�nm�ag throug8 tl�e pnvpetiq is nat�ad aa the�y�Reatoa Maps. Da�v�o4 fia�n t�e sibe tbe sh�n is�tod a�the Cgy 1�as a ca�egacy 4�n. Tbe�d baH't�for Cabegaq 4 str�m is 35 f�. As sach t�e atre�am ba�r woald be�w�tbm f�e 30ft w�and� 518 North 59�Street�SeaEtle,Washington 98103• Wwree(t06y783-i036 ernat!aldernw�+oomcastoet � Ms.Lindu Pillo Apri! 19,20U7 VNe trust the iunformatian presentad is suf�"icient £or your carrent neals. If you have arry quc�tions ar rc�sire additional ir�orrnati�q please call. SincerclY Y��, ALll N1�V �p �� P. Munger L� V Pro�ect Sccer�h�t Project No. 44407 Page No. 2 7.0 OTHER PERMITS The following permits and/or approvals are thought to be required as part of this project: • Construction Stormwater General Permit(Department of Ecology) • Postmaster Approval • Building Permits • Right of Way Permit 8.0 ESC ANALYSIS AND DESIGN TESC measures are put into place to prevent sediment from leaving the site. The site is generally flat. The proposed TESC plan will include, but not be limited to, the follo��ing guidelines set in the 2005 KCWSWDM in order to comply with Core Requirement No. 5. Clearing Limits — The clearing limits are on the engineering plans and �vill be flagged in the field. Cover Measures — Cover measures are specified on the TESC plan set and will be implemented in the field as necessary. Perimeter Protection —The silt fence and clearing limits will be shown on the TESC plans and implemented in the field. Traftic Area Stabilization — Traffic area stabilization will be addressed by a stabilized construction entrance. Sediment Retention — Retention �vill be established by silt fences around the perimeter and catch basin inserts that will control of the on-site sediment-laden water. Surface Water Collection — Runoff will be routed to the collection ditches and routed to a sediment trap if necessary. Dewatering Control —Any water from dewatering shall be filtered or contained so sediment can filter out prior to discharge downstream. Dust Control— Dust control by splinklering will be provided as needed. Wet Season Construction: Infrastructure construction will be conducted in the summer months. Any construction planned during the wet season will be according to King County and the Citv of Renton standards. Construction Within Sensitive Areas and Buffers: Minimal construction is proposed within the sensitive area buffer. Enhancement planting is proposed and �vill not impact the buffer in a negative manner. Maintenance: Maintenance requirements are detailed in the TESC notes on the engineering plans. Final Stabilization: Upon completion of the project, all disturbed areas will be stabilized and Best Management Practices removed if appropriate. KCRTS Command CREATE a new Time Series ------------------------ Production of Runoff Time Series Project Location : Sea-Tac Computing Series : 13040TESC.tsf � Regional Scale Factor : 1. 00 Data Type : Reduced Creating 15-minute Time Series File Loading Time Series File:C: \KC SWDM\KC DATA\STTF15R.rnf . � Till Forest 1 . 91 acres Loading Time Series File:C: \KC SWDM\KC DATA\STTG15R.rnf . Till Grass 0. 96 acres Loading Time Series File:C: \KC SWDM\KC DATA\STEI15R.rnf . Impervious 0. 86 acres -------------- Total Area : 3.73 acres Peak Discharge: 1. 64 CFS at 6:30 on Jan 9 in Year 8 i Storing Time Series File: 13040TESC.tsf . Time Series Computed KCRTS Command Enter the Anal sis TOOLS Module Y Analysis Tools Command ' ---------------------- Compute PEAKS and Flow Frequencies ---------------------------------- Loading Stage/Discharge curve: 13040tesc.tsf . Flow Frequency Analysis -------------------------------------------------------- Time Series File: 13040tesc. tsf Project Location:Sea-Tac Frequencies & Peaks saved to File: 13040TESC.pks . Analysis Tools Command ---------------------- ' RETURN to Previous Menu ----------------------- KCRTS Command eXit KCRTS Program 13040TESC.pks Flow Frequency analysis Time Series File:13040tesc.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.488 6 2/09/Ol 12:30 1.64 1 100.00 0.990 0. 347 7 1/05/02 15:00 1.06 2 25.00 0.960 1.06 2 12/08/02 17: 15 0.654 3 10.00 0.900 0. 330 8 8/23/04 14: 30 0. 588 4 5.00 0.800 0.654 3 11/17/04 5:00 0. 522 5 3.00 0.667 0. 522 5 10/27/05 10:45 0.488 6 2.00 0. 500 0. 588 4 10/25/06 22:45 0.347 7 1.30 0.231 1.64 1 1/09/08 6:30 0. 330 8 1.10 0.091 computed Peaks 1.45 50.00 0.980 Requ_red S�itace Area �SA1 � �.��r K��St"��Df�,� D �. . � SA=2,080 sf per cfs of inflow O� =0 488 cfs SA �1�K.. �� , i�, �r Page 1 9.o Bo�vv Qu��T�TiEs The City of Renton Bond Quantity Worksheet is included «-ithin this section. S15 Web date 02/22/201; Site Improvement Bond Quantity Worksheet � King County Department of Permitting & Environmental Review 35030 SE Douglas Street, Suite 210 Snoqualmie, Washington 98065-9266 For alternate formats, call 206-296-6600. 206-296-6600 TTY Relay 711 Pro�ect Name: Chelan Creek PUD Date: 8/14/2015 �ocat�on: Renton, WA Project No.: LUA 08 067 Activity No.: U 15005174 Note: All prices include labor, equipment, materials, overhead and Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. x yes no If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 Unit prices updated: 02/12/02 , Version: 11/26/2008 IKCBQW.xIs Report Date: 8/14/2015 S15 Web date: 02/22/201; Site Improvement Bond Quantity Worksheet Unit #of Reference# Price Unit Quantity Applications Cost EROSION/SEDIMENT CONTROL Number Backfill &compaction-embankment ESC-1 $ 5.62 CY Check dams, 4"minus rock ESC-2 SWDM 5.4.6.3 $ 67.51 Each 3 1 203 Crushed surfacing 1 1/4"minus ESC-3 WSDOT 9-03.9(3) $ 85.45 CY Ditchin ESC-4 $ 8.08 CY 50 1 404 Excavation-bulk ESG5 $ 1.50 CY Fence, silt ESC-6 SWDM 5.4.3.1 $ 1.38 LF 1150 1 1587 Fence, Temporary(NGPE) ESC-7 $ 1.38 LF Hydroseedin ESC-8 SWDM 5.4.2.4 $ 0.59 SY 10000 1 5900 Jute Mesh ESC-9 SWDM 5.4.2.2 $ 1.45 SY Mulch, by hand, straw, 3"deep ESC-10 SWDM 5.4.2.1 $ 2.01 SY Mulch, b machine, straw, 2"deep ESC-11 SWDM 5.4.2.1 $ 0.53 SY Piping, temporary, CPP, 6" ESC-12 $ 10.70 LF Piping,tempora , CPP, 8" ESC-13 $ 16.10 LF Piping,temporary, CPP, 12" ESC-14 $ 20.70 LF Plastic coverin , 6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 $ 2.30 SY Rip Rap, machine placed; slopes ESC-16 WSDOT 9-13.1(2) $ 39.08 CY Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4.1 $ 1,464.34 Each 2 1 2929 Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 $ 2,928.68 Each Sediment pond riser assembl ESC-19 SWDM 5.4.5.2 $ 1,949.38 Each 1 1 1949 Sediment tra , 5' hi h berm ESC-20 SWDM 5.4.5.1 $ 17.91 LF 100 1 1791 Sed.trap, 5'high, riprapped spillway berm section ESC-21 SWDM 5.4.5.1 $ 68.54 LF 15 1 1028 Seeding, by hand ESC-22 SWDM 5.4.2.4 $ 0.51 SY Soddin , 1"deep, level ground ESC-23 SWDM 5.4.2.5 $ 6.03 SY Sodding, 1"deep, sloped ground ESC-24 SWDM 5.4.2.5 $ 7.45 SY TESC Supervisor ESC-25 $ 74.75 HR 16 1 1196 Water truck, dust control ESC-26 SWDM 5.4.7 $ 97.75 HR 16 1 1564 WRITE-IN-ITEMS **** (see paae 91 Each ESC SUBTOTAL: $ 18,550.69 30% CONTINGENCY&MOBILIZATION: $ 5,565.21 ESC TOTAL: $ 24,115.90 COLUMN: A Page 2 of 9 Unit prices updated: 02/12/02 Version: 11/26/2008 KCBoW.xls Report Date: 8/14/2015 I Site Improvement Bond Quantity Worksheet Webdate 12/02/2008 Existing Future Public Private Quantity Completed Right-of-Way Right of Way Improvements (Bond Reduction)" &Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost GENERAL ITEMS No. Backfill&Com action-embankment GI-1 $ 5.62 CY Backfill&Com action-trench GI-2 $ 8.53 CY Clear/Remove Brush,b hand GI-3 $ 0.36 SY Clearin /Grubbin /Tree Removal GI-4 $ 8,876.16 Acre 0.8 7,100.93 1.5 13,314.24 Excavation-bulk GI-5 $ 1.50 CY 2000 3,000.00 Excavation-Trench GI-6 $ 4.06 CY Fencin ,cedar,6'hi h GI-7 $ 18.55 LF Fencin ,chain link,vin I coated, 6'hi h GI-8 $ 13.44 LF 420 5,644.80 Fencin ,chain link, ate,vin I coated, 2 GI-9 $ 1,271.81 Each 1 1,271.81 Fencin ,s lit rail,3'hi h GI-10 $ 12.12 LF 2150 26,058.00 Fill&com act-common barrow GI-11 $ 22.57 CY Fill&compact- ravel base GI-12 $ 25.48 CY Fill&com act-screened to soil GI-13 $ 37.85 CY Gabion, 12"dee ,stone filled mesh GI-14 $ 54.31 SY Gabion, 18"deep,stone filled mesh GI-15 $ 74.85 SY Gabion,36"dee ,stone filled mesh GI-16 $ 132.48 SY Gradin ,fine,b hand GI-17 $ 2.02 SY Gradin ,fine,with rader GI-18 $ 0.95 SY 1450 1,377.50 250 237.50 Monuments.3'lon GI-19 $ 135.13 Each 1 135.13 Sensitive Areas Si n GI-20 $ 2.88 Each 25 72.00 Soddin , 1"deep,slo ed round GI-21 $ 7.46 SY Surve in ,line 8 rade GI-22 $ 788.26 Da 2 1,576.52 2 1,576.52 Surve in ,lot location/lines GI-23 $ 1,556.64 Acre 2 3,113.28 Traffic control crew 2 fla ers) GI-24 $ 85.18 HR 24 2,044.32 Trail,4"chi ed wood GI-25 $ 7.59 SY 500 3,795.00 Trail,4"crushed cinder GI-26 $ 8.33 SY Trail,4"top course GI-27 $ 8.19 SY Wall,retainin ,concrete GI-28 $ 44.16 SF Wall,rockery GI-29 $ 9.49 SF 300 2,847.00 Page 3 of 9 SUBTOTAL 24,998.01 48,166.54 Unit prices updated: 02/12/02 , "KCC 27A authorizes only one bond reduction. Version: 11/26/08 KCBQW xls Report Date 8/14/2015 Site Improvement Bond Quantity Worksheet Webdate 12/02/2008 Existing Future Public Private Bond Reduction' Right-of-way Right of Way Improvements &Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost ROADIMPROVEMENT No. AC Grindin ,4'wide machine<1000s RI-1 $ 28.00 SY 440 12,320.00 AC Grindin ,4'wide machine 1000-200 RI-2 $ 15.00 SY AC Grindin ,4'wide machine>2000s RI-3 $ 7.00 SY ! AC Removal/Disposal/Repair RI-4 $ 67.50 SY 50 3,375.00 II Barricade, e I RI-5 $ 30.03 LF Barricade,t e III Permanent RI-6 $ 45.05 LF Curb&Gutter,rolled RI-7 $ 17.00 LF Curb&Gutter,vertical RI-8 $ 12.50 LF 682 8,525.00 500 6,250.00 350 4,375.00 Curb and Gutter,demolition and dis osal RI-9 $ 18.00 LF Curb,extruded as halt RI-10 $ 5.50 LF Curb,eMruded concrete RI-11 $ 7.00 LF Sawcut,as halt,3"de th RI-12 $ 1.85 LF 800 1,480.00 Sawcut,concrete, er 1"depth RI-13 $ 1.69 LF Sealant,asphalt RI-14 $ 1.25 LF 600 750.00 Shoulder,AC, see AC road unit rice RI-15 $ - SY Shoulder, ravel,4"thick RI-16 $ 15.00 SY Sidewalk,4"thick RI-17 $ 35.00 SY 375 13,125.00 Sidewalk,4"thick,demolition and dis os RI-18 $ 29.50 SY Sidewalk,5"thick RI-19 $ 38.50 SY 115 4,427.50 42 1,617.00 Sidewalk,5"thick,demolition and dis os RI-20 $ 37.50 SY Si n,handica RI-21 $ 85.28 Each Stri in , er stall RI-22 $ 5.82 Each Stripin ,thermo lastic, for crosswalk) RI-23 $ 2.38 SF Striping,4"reflectorized line RI-24 $ 0.25 LF , Page 4 of 9 SUBTOTAL 39,575.00 10,677.50 5,992.00 Unit prices updated: 02/12/02 'KCC 27A authorizes only one bond reduction. Version 11/26/08 KCBQW.xIs Report Date: 8/14/2015 � � Site Improvement Bond Quantity Worksheet Webdate 12/02/2008 Existing Future Public Private Bond Reduction• Right-of-way Right of Way Improvements 8�Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost ROAD SURFACING (4"Rock=2.5 base&1.5"top course) For'93 KCRS(6.5"Rock=5"base&1.5"top course) For KCRS'93, additional 2.5"base add RS-1 $ 3.60 SY AC Overla , 1.5"AC RS-2 $ 11.25 SY AC Overla ,2"AC RS-3 $ 15.00 SY 440 6,600.00 AC Road,2",4"rock,First 2500 SY RS-4 $ 21.00 SY AC Road,2",4"rock,Qt .over 2500SY RS-5 $ 19.00 SY AC Road,3",4"rock,First 2500 SY RS-6 $ 23.30 SY 918 21,389.40 800 18,640.00 AC Road,3",4"rock,Qt .over 2500 SY RS-7 $ 21.00 SY AC Road,5",First 2500 SY RS-8 $ 27.60 SY AC Road,5",Qt .Over 2500 SY RS-9 $ 25.00 SY AC Road,6",First 2500 SY S-1 $ 33.10 SY � AC Road,6",Q .Over 2500 SY RS-1 $ 30.00 SY Asphalt Treated Base,4"thick RS-1 $ 20.00 SY Gravel Road,4"rock,First 2500 SY S-1 $ 15.00 SY Gravel Road,4"rock,Q .over 2500 SY S-1 $ 8.50 SY PCC Road,5",no base,over 2500 SY S-1 $ 27.00 SY PCC Road, 6",no base,over 2500 SY S-1 $ 25.50 SY Thickened Edge RS-1 $ 8.60 LF Page 5 of 9 SUBTOTAL 6,600.00 21,389.40 18,640.00 Unit prices updated: 02/12/02 "KCC 27A authorizes only one bond reduction. Version: 11/26/08 KCBQW.xIs Report Date: 8/14/2015 � � Site Improvement Bond Quantity Worksheet Webdate 12/02/2008 Existing Future Public Private Bond Reduction" Right-of-way Right of Way Improvements 8�Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost DRAINAGE (CPP=Corrugated Plastic Pipe,N12 or Equivalent) For Culvert prices, Average of 4'cover was assumed.Assume erforated PVC is same price as solid pipe. Access Road,R/D D-1 $ 21.00 SY 227 4,767.00 Bollards-fixed D-2 $ 240.74 Each Bollards-removable D-3 $ 452.34 Each ' CBs include frame and lid CB T e I D-4 $ 1,257.64 Each 6 7,545.84 CB T pe IL D-5 $ 1,433.59 Each CB T e II,48"diameter D-6 $ 2,033.57 Each for additional de th over 4' D-7 $ 436.52 FT CB T e II,54"diameter D-S $ 2,192.54 Each 1 2,192.54 for additional depth over 4' D-9 $ 486.53 FT CB T e II,60"diameter D-10 $ 2,351.52 Each for additional de th over 4' D-11 $ 536.54 FT CB T e II,72"diameter D-12 $ 3,212.64 Each for additional de th over 4' D-13 $ 692.21 FT Throu h-curb Inlet Framework(Add) D-14 $ 366.09 Each Cleanout,PVC,4" D-15 $ 130.55 Each Cleanout,PVC,6" D-16 $ 174.90 Each 14 2,448.60 Cleanout,PVC,8" D-17 $ 224.19 Each Culvert,PVC,4" D-18 $ 8.64 LF Culvert,PVC,6" D-19 $ 12.60 LF Culvert,PVC, 8" D-20 $ 13.33 LF Culvert,PVC, 12" D-21 $ 21.77 LF Culvert,CMP,8" D-22 $ 17.25 LF Culvert,CMP, 12" D-23 $ 26.45 LF Culvert,CMP, 15" D-24 $ 32.73 LF Culvert,CMP, 18" D-25 $ 37.74 LF Culvert,CMP,24" D-26 $ 53.33 LF Culvert,CMP,30" D-27 $ 71.45 LF Culvert,CMP,36" D-28 $ 112.11 LF Culvert,CMP,48" D-29 $ 140.83 LF Culvert,CMP,60" D-30 $ 235.45 LF Culvert,CMP,72" D-31 $ 302.58 LF Page 6 of 9 SUBTOTAL 14,505.38 2,448.60 Unit prices updated 02l12/02 `KCC 27A authori2es only one bond reduction. Version: 11/26/08 KCBQW.xIs Report Date: 8/14/2015 Site Improvement Bond Quantity Worksheet Webdate 12/02/2008 Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements DRAINAGE CONTINUED 8�Drainage Facilities Quant. No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost Culvert,Concrete,8" D-32 $ 21.02 LF Culvert,Concrete, 12" D-33 $ 30.05 LF Culvert,Concrete, 15" D-34 $ 37.34 LF Culvert,Concrete, 18" D-35 $ 44.51 LF Culvert,Concrete,24" D-36 $ 61.07 LF j Culvert,Concrete,30" D-37 $ 104.18 LF ' Culvert,Concrete,36" D-38 $ 137.63 LF Culvert,Concrete,42" D-39 $ 158.42 LF Culvert,Concrete,48" D-40 $ 175.94 LF � Culvert,CPP,6" D-41 $ 10.70 LF Culvert,CPP,8" D-42 $ 16.10 LF Culvert,CPP, 12" D-43 $ 20.70 LF 158 3270.6 475 9832.5 Culvert,CPP, 15" D-44 $ 23.00 LF Culvert,CPP, 18" D-45 $ 27.60 LF Culvert,CPP,24" D-46 $ 36.80 LF Culvert,CPP,30" D-47 $ 48.30 LF Culvert,CPP,36" D-48 $ 55.20 LF Ditchin D-49 $ 8.08 CY Flow Dis ersal Trench (1,436 base+ D-50 $ 25.99 LF French Drain 3'de th) D-51 $ 22.60 LF I Geote�ile,laid in trench, ol ro lene D-52 $ 2.40 SY Infiltration ond testin D-53 $ 74.75 HR Mid-tank Access Riser,48"dia, 6'deep D-54 $ 1,605.40 Each Pond Overtlow S illwa D-55 $ 14.01 SY 20 280.2 Restrictor/Oil Se arator, 12" D-56 $ 1,045.19 Each 1 1045.19 Restrictor/Oil Separator, 15" D-57 $ 1,095.56 Each Restrictor/Oil Se arator, 18" D-58 $ 1,146.16 Each Ri ra , laced D-59 $ 39.08 CY 25 977 Tank End Reducer(36"diameter) D-60 $ 1,000.50 Each Trash Rack, 12" D-61 $ 211.97 Each 2 423.94 Trash Rack, 15" D-62 $ 237.27 Each Trash Rack, 18" D-63 $ 268.89 Each Trash Rack,21" D-64 $ 306.84 Each Page 7 of 9 SUBTOTAL 3270.6 12558.83 Unit prices updated: 02/12/02 "KCC 27A authorizes only one bond reduction. Version: 11/26/08 KCBQW.xIs Report Date 8/14/2015 I Site Improvement Bond Quantity Worksheet Webdate 12/02/2008 Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements 8�Draina e Facilities Quant. Unit Price Unit Quant. Price Quant. Cost Quant. Cost Com lete Cost PARKING LOT SURFACING No. 2"AC,2"to course rock&4"borrow PL-1 $ 21.00 SY 2"AC, 1.5" to course&2.5"base cour PL-2 $ 28.00 SY 4"select borrow PL-3 $ 4.55 SY 1.5"to course rock 8 2.5"base course PL-4 $ 11.41 SY UTILITY POLES 8�STREET LIGHTING Utili pole relocation costs must be accompanied b Franchise Utili 's Cost Statement Utilit Pole s Relocation UP-1 Lum Sum Street Li ht Poles w/Luminaires UP-2 Each WRITE-IN-ITEMS Such as detention/water uali vaults. No. Stormfilter CB-1 cartrid e WI-1 $ 5,500.00 Each 1 5,500.00 Stormfilter CB-2 cartrid e WI-2 $ 9,800.00 Each 2 19600 WI-3 CY WI-4 LF WI-5 FT WI-6 WI-7 WI-8 WI-9 WI-10 SUBTOTAL 19,600.00 5,500.00 SUBTOTAL(SUM ALL PAGES): 94,043.61 107,297.65 32,580.60 30%CONTINGENCY&MOBILIZATION: 28,213.08 32,189.30 9,774.18 GRANDTOTAL: 122,256.69 139,486.95 42,354.78 CO�UMN: B C D E Page 8 of 9 Unit prices updated: 02/12/02 *KCC 27A authorizes only one bond reduction. Version: 11/26/08 KCBQW.xIs Report Date: 8/14/2015 I � Web date: 12/02/2008 Site Improvement Bond Quantity Worksheet Original bond computations prepared by: Name: Cara Visintainer PE �ate: 8/14/2015 PE Registration Number: 42842 Tel.#: 253-848-4282 Firm Name: CES NW Address: 310 29th ST NE, Puyallup, WA 98372 Project No: LUA 08 067 ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND" PUBLIC ROAD&DRAINAGE AMOUNT BOND'AMOUNT MAINTENANCE/DEFECT BOND" REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control (ESC) (A) $ 24,115.9 TEMPORARY OCCUPANCY*** Existing Right-of-Way Improvements (B) $ 122,256.7 Future Public Right of Way& Drainage Facilities (C) $ 139,486.9 Private Improvements (D) $ 42,354.8 Calculated Quantity Completed (E) $ - Total Right-of Way and/or Site Restoration Bond'/"" (A+B) $ 146,372.6 (First$7,500 of bond'shall be cash. PerFormance Bond"Amount (A+B+C+D) = TOTAL (T) $ 328,214.3 T x 0.30 $ 98,464.3 OR mimum on amount is Reduced Performance Bond*Total*" (T-E) $ 328,214.3 Use larger o x o or - (B+C) X Maintenance/Defect Bond`Total 0.25= $ 65,435.9 NAME OF PERSON PREPARING BOND"REDUCTION: Date: *NOTE: The word"bond"as used in this document means a financial guarantee acceptable to King County. "NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition, corrective work,both on-and off-site needs to be included. Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged,some estimated costs for restoration needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity. ***NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised by major design changes. REQUIRED BOND'AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES Page 9 of 9 Unit prices updated: 02/12/02 Check out the DDES Web site at www.kinpcountv.aov/permits Version: 11/26/08 KCBQW.xIs Report Date: 8/14/2015 i --J � 10.0 OPERATIONS AND MAINTENANCE MANUAL ' The drainage facilities on this project will be maintained by the homeo�vners. Maintenance instructions are included �vithin this section. , � i _' I ,-� I � .J .__� , , � I _� , , ; ; � , - . I ' � . . � � '� �: J ; , il ( I � ' � ! I -� „ : � i , � ' '._J I { KING ('OUN'IY, WAS111NG'ION. SURI�nCI; Wn'II:R t)I:SI<�N M�1NUnl. I APPENDIX A '� MAINTENANCE RE UIREMENTS FOR FLOW Q CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 1 - DETENTION PONDS Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed General Trash&Debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet(this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Poisonous Vegetation Any poisonous or nuisance vegetation which may No danger of poisonous vegetation or Noxious Weeds constitute a hazard to County personnel or the where County personnel or the public. public might normally be. ' Coordination with Seattle-King County Heallh Department Contaminants and Oil,gasoline,or other contaminants of one gallon No contaminants present other than Pollution or more, or any amount found that could: a surface film. (Coordination with 1)cause damage to plant,animal,or marine life; Seattle/King County Health 2)constitute a fire hazard; or 3�be flushed Department) downstream during rain storms. Unmowed if facility is located in private residential area, When mowing is needed, Grass/Ground Cover mowing is needed when grass exceeds 18 grass/ground cover should be inches in height. In other areas,the general mowed to 2 inches in height. policy is to make the pond site match adjacent Mowing of selected higher use areas ground cover and terrain as long as there is no rather than the entire slope may be interference with the function of the facility. acceptable for some situations. Rodent Holes Any evidence of rodent holes if facility is acting Rodents destroyed and dam or berm as a dam or berm,or any evidence of water repaired. (Coordination with piping through dam or berm via rodent holes or SeattlelKing County Health other causes. Department) Insects When insects such as wasps and hornets Insects destroyed or removed from interfere with maintenance activities. Mosquito site. Mosquito control: Swallow complaints accompanied by presence of high nesting boxes or approved larvicide mosquito larvae concentrations(aquatic phase}. applied. Tree Growth Tree growth threatens integrity of berms acting Trees do not hinder maintenance as dams,does not allow maintenance access, or activities. Harvested trees should interferes with maintenance activity(i.e.,slope be recycled into mulch or other mowing,silt removal,vactoring, or equipment beneficial uses(e.g.,alders for movements). If trees are a threat to berm firewood). integrity or not interfering with access,leave trees alone. 2005 SnrfTce W�ter I�esign Manual—Appendix A 1/24/2005 A-1 l�PPI;NI)IX n MAIN'17�,NAN('1: RI:(1UIR1•:MI:N I S 1'LOW C'ON"I�ROI..CONVI:YANCI?,ANI)W(?I'AC'll.11'IF.S NO. 1 -DETENTION PONDS Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When , Component Mafntenance Is Performed Side Slopes of Pond Erosion Eroded damage over 2 inches deep where cause Slopes should be stabilized by using of damage is stili present or where there is appropriate erosion control ' potential for continued erosion. measure(s);e.g., rock reinforcement, planting of grass, Any erosion observed on a compacted berm compaction. embankment. I If erosion is occurring on compacted berms a licensed civil engineer should be consulted to resolve source of erosion. Storage Area Sediment Accumulated sediment that exceeds 10%of the Sediment cleaned out to designed designed pond depth. pond shape and depth; pond reseeded if necessary to control erosion. Liner Damage Linei is visible and has more than three'/,-inch Liner repaired or replaced. (If Applicable) holes in it. Pond Berms(Dikes) Settlement Any part of berm that has settled 4 inches lower Dike should be built back to the than the design elevation. Settling can be an design elevation. indication of more severe problems with the berm ' or outlet works. A licensed civil engineer should be consulted to determine the source of the settlement. Emergency Tree Growth Tree growth on emergency spillways create Trees should be removed. If root Overflow/Spillway blockage problems and may cause failure of the system is small(base less than 4 and Berms over 4 berm due to uncontrolled overtopping. inches)the root system may be left feet in height. in place. Otherwise the roots should Tree growth on berms over 4 feet in height may be removed and the berm restored. lead to piping through the berm which could lead A licensed civil engineer should be to failure of the berm. consulted for proper berm/spillway restoration. Emergency Rock Missing Only one layer of rock exists above native soil in Replace rocks to design standards. OverflowlSpillway area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. 1/24/2005 2005 Surface Water Design Manual—Appendix A A-2 nPPI:NUIX n A4AIN 1'I?NANCG RI�.OUIRI:MI:NI'S I�l)Ii I�LOW CON'I'ROl..CONVI;YANCI:.ANI)Wl�PAC'ILI'I Il:ti NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Probfem Conditlon When Maintenance is Needed Results Expected When Component Maintenance is Performed General Trash and Debris Distance between debris build-up and bottom of All trash and debris removed. (Inciudes Sediment) orifice plate is less than 1.5 feet. Structural Damage Struclure is not securely attached to manhole Structure securely attached to wall wall and outiet pipe structure should support at and outlet pipe. least 1,000 Ibs of up or down pressure. Structure is not in upright position(allow up to Structure in correct position. 10%from plumb). Connections to outlet pipe are not watertight and Connections to outlet pipe are water show signs of rust. tight; structure repaired or replaced and works as designed. Any holes—other than designed holes—in the Structure has no holes other than structure. designed holes. Cleanout Gate Damaged or Missing Cleanout gate is not watertight or is missing. Gate is watertight and worlcs as I designed. Gate cannot be moved up and down by one Gate moves up and down easily and maintenance person. is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Gate is rusted over 50°/a of its surface area. Gate is repaired or replaced to meet design standards. Or�ce Plate Damaged or Missing Control device is not working properly due to Plate is in place and works as , missing,out of place,or bent orifice plate. designed. ' Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and blocking the plate. works as designed. Overftow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all obstructions and potential of blocking)the overflow pipe. works as designed. Manhole See"Detention Tanks See°Detention Tanks and Vaults"Table No.3 See"Detention Tanks and Vaults" and Vaults" Table No. 3 I ;�.:� I i. ��ij �� 1 2005 Surface�'�'ater Design Manual–Appendix A 1/24/2005 A-5 1;"I \I�I\ 1 �1 \I\II V' V\(�I� i:i t)t IIZI \il \I� I I ��\1 ( ��ti II:(>I . l ti\\ I l� \\(�I-. :1\I) \1t� I �1l II II II ti NO. 5-CATCH BASINS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash 8 Debris Trash or debris of more than'/z cubic foot which No Trash or debris located (Includes Sediment) is located immediateiy in front of the catch basin immediately in front of catch basin opening or is blocking capacity of the basin by opening. more than 10%. Trash or debris(in the basin)that exceeds�/3 the No trash or debris in the catch depth from the bottom of basin to invert the basin. lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe blocking inlet and outlet pipes free of trash or more than'/3 of its height. debris. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases(e.g., methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Structure Damage to Corner of frame extends more than'/.inch past Frame is even with curb. Frame andlor Top curb face into the street(If applicable). Slab Top slab has holes larger than 2 square inches Top slab is free of holes and cracks. or cracks wider than '/.inch(intent is to make sure all material is running into basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than'/,inch of the frame from the top slab. Cracks in Basin Cracks wider than'/:inch and longer than 3 feet, Basin replaced or repaired to design WaIIs/Bottom any evidence of soil particles entering catch standards. basin through cracks,or maintenance person judges that structure is unsound. Cracks wider than'/Z inch and longer than 1 foot No cracks more than'/4 inch wide at at the joint of any inleUoutlet pipe or any the joint of inleVoutlet pipe. evidence of soil particles entering catch basin through cracks. SettlemenU Basin has settled more than 1 inch or has rotated Basin replaced or repaired to design Misalignment more than 2 inches out of alignment. standards. Fire Hazard Presence of chemicals such as natural gas,oil No flammable chemicals present. and gasoline. Vegetation Vegetation growing across and blocking more No vegetation blocking opening to than 10%of the basin opening. basin. Vegetation growing in inleUoutlet pipe joints that No vegetation or root growth is more than 6 inches tall and less than 6 inches present. apart. Pollution Nonflammable chemicals of more than Yz cubic No pollution present other than foot per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missing or only partially in place.Any Catch basin cover is closed open catch basin requires maintenance. Locking Mechanism Mechanism cannot be opened by on Mechanism opens with proper tools. Not Working maintenance person with proper tools.Bolts into frame have less than'/z inch of thread. Cover Difflcult to One maintenance person cannot remove lid after Cover can be removed by one Remove applying 80 Ibs.of lift; intent is keep cover from maintenance person. sealing off access to maintenance. Ladder Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, Ladder meets design standards and misalignment, rust,cracks,or sharp edges. allows maintenance person safe access. 1r2�4i2005 2005 Surface Water Design Manual—Appendix A �1-6 ;�i�i��:Ni>ix ;� ��iniv i�i��:�»ci�. iti��i�zi�.n�u�;��rti i�uit i�i ��n� ��ti i itui_. ��u�vi�.�';�r��i:. ,�t�i� �� i�;��i� t i it�s NO. 5-CATCH BASINS Mafntenance Defect or Problem Cond(tions When Maintenance is Needed Results Expected When Component Maintenance is performed Metal Grates Unsafe Grate Grate with opening wider than�/e inch. Grate opening meets design (ItApplicable) Opening standards. Trash and Debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. Damaged or Missing. Grate missing or broken member{s)of the grate. Grate is in place and meets design standards. NO. 6- DEBRIS BARRIERS (E.G., TRASH RACKS) Maintenance Defect or Problem Conditfon When Maintenance is Needed Results Expected When Component Maintenance is Performed. General Trash and Debris Trash or debris that is plugging more than 20% Barrier clear to receive capacity of the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. than'/,inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50% Repair or replace barrier to design deterioration to any part of barrier. standards. NO. 7-ENERGY DISSIPATERS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed. External: Rock Pad Missing or Moved Only one layer of rock exists above native soil in Replace rocks to design standards. Rock area five square feet or larger,or any exposure of native soil. Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20%of the Pipe cleaned/flushed so that it Sediment design depth. matches design. Not Discharging Visual evidence of water discharging at Trench must be redesigned or Water Properly concentrated points along trench(normal rebuilt to standards. condition is a"sheet flow"of water along trench). Intent is to prevent erosion damage. Perforations Plugged. Over'/z of perforations in pipe are plugged with Clean or replace perforated pipe. debris and sediment. Water Flows Out Top Maintenance person observes water flowing out Facility must be rebuilt or of"Distributor"Catch during any storm less than the design storm or redesigned to standards. Basin. its causing or appears likely to cause damage. Receiving Area Over- Water in receiving area is causing or has No danger of landslides. Saturated potential of causing landslide problems. ' Intemal: Manhole/Chamber Worn or Damaged Structure dissipating flow deteriorates to'/z or Replace structure to design Post. Bafftes,Side of original size or any concentrated worn spot standards. Chamber exceeding one square foot which woutd make structure unsound. � ' 2005 Surface Water Design Manual—Appendia A U24/2005 A-7 API'I?NI)IX n MAIN'1'I:N/�NCI;R1:C)UIRI:MI:N I'ti NLOW C'ON 1'ROI..CONVIiYANCIi.ANI) WO PA('ll.l l�lli5 � NO. 8-FENCING Mafntenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Missing or Broken Any defect in the fence that permits easy entry to Parts in place to provide adequate Parts a facility. security. Erosion Erosion more than 4 inches high and 12-18 No opening under the fence that ' inches wide permitting an opening under a fence. exceeds 4 inches in height. � Wire Fences Damaged Parts Post out of plumb more than 6 inches. Post plumb to within 1 Y:inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence(including post,top rails, and Fence is aligned and meets design fabric)more than 1 foot out of design alignment. standards. Missing or loose tension wire. Tension wire in place and holding fabric. Missing or loose barbed wire that is sagging Barbed wire in place with less than more than 2'/:inches between posts. '/.inch sag between post. Extension arm missing, broken,or bent out of Extension arm in place with no shape more than 1Y:inches. bends largerthan'/.inch. Deteriorated Paint or Part or parts that have a rusting or scaling Structurally adequate posts or parts Protective Coating condition that has affected structural adequacy. with a uniform protective coating. Openings in Fabric Openings in fabric are such that an 8-inch No openings in fabric. diameter ball could fit through. � NO. 9-GATES Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Damaged or Missing Missing gate or tocking devices. Gates and Locking devices in place. Members Broken or missing hinges such that gate cannot Hinges intact and lubed.Gate is be easily opened and closed by a maintenance working freely. person. Gate is out of plumb more than 6 inches and Gate is aligned and vertical. more than 1 foot out of design alignment. Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands,and ties in place. Openings in Fabric See"Fencing"Table No.8 See"Fencing"Table No.8 1/24/2005 2005 Surface Water Dcsign Manual—Appendix n A-8 i11'1'I�:NI)IX n �1�11N Il:NntiC'i�:RI:t1UIIZI�:A41�N"fS iOIt 1�1,c��4('O1�I1ZOI,.('UNVLY�IN('I;.;1N1)�Vc1 I ��('iLl I II S NO. 10-CONVEYANCE PIPES AND DITCHES Malntenance Defect or Problem Conditions When Mafntenance fs Needed Results Expected When Component Maintenance is Pertormed Pipes Sediment&Debris Accumulated sediment that exceeds 20%of the Pipe cleaned of all sediment and diameter of the pipe. debris. Vegetation Vegetation that reduces free movement of water All vegetation removed so water through pipes. flows freely through pipes. Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced. more than 50%deterioration to any part of pipe. Any dent that decreases the cross section area Pipe repaired or replaced. of pipe by more than 20%. Open Ditches Trash&Debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion Damage to See"Detention Ponds"Table No. 1 See"Detention Ponds"Table No. 1 Slopes Rock Lining Out of Maintenance person can see native soil beneath Replace rocks to design standards. Place or Missing(If the rock lining. Applicable). NO. 11 -GROUNDS {LANDSCAPING) i Malntenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Weeds Weeds growing in more than 20%of the Weeds present in less than 5%of � (Nonpoisonous, not landscaped area(trees and shrubs only). the landscaped area. noxious) Safety Hazard Any presence of poison ivy or other poisonous No poisonous vegetation present in vegetation. landscaped area. Trash or Litter Paper,cans, bottles,totaling more than 1 cubic Area clear of litter. � foot within a landscaped area(trees and shrubs only)of 1,000 square feet. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5% broken which affect more than 25%of the total of total foliage with split or broken � � foliage of the tree or shrub. limbs. Trees or shrubs that have been blown down or Tree or shrub in place free of injury. knocked over. Trees or shrubs which are not adequately Tree or shrub in place and supported or are leaning over, causing exposure adequately supported;remove any of the roots. dead or diseased trees. 2005 Surface Water Design Manual—Appendix A 1/24/2005 A-9 /�PI'I:NI)IY �1 MnINfI:NnNCI:fti:(1l)IR1:�11?N151�LO\�'l'ONl ltc)I..(�ONVI:1'nN('I:. nNU \4'111��1c'll.l l ll•:ti NO. 12-ACCESS ROADS Maintenance Defect or Probiem CondiUon When Maintenance is Needed Results Expected When Component Maintenance is Performed General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway free of debris which could square feet(i.e.,trash and debris would fill up damage tires. one standards size garbage can). Blocked Roadway Debris which could damage vehicle tires(glass Roadway free of debris which could or metal). damage tires. Any obstruction which reduces clearance above Roadway overhead clear to 14 feet road surface to less than 14 feet. high. Any obstruction restricting the access to a 10-to Obstruction removed to allow at 12-foot width for a distance of more than 12 feet least a 12-foot access. or any point restricting access to less than a 10- foot width. Road Surface Settlement,Potholes, When any surtace defect exceeds 6 inches in Road surface uniformly smooth with Mush Spots, Ruts depth and 6 square feet in area. In general,any no evidence of settiement, potholes, surface defect which hinders or prevents mush spots,or ruts. maintenance access. Vegetation in Road Weeds growing in the road surface that are more Road surface free of weeds taller Surface than 6 inches tall and less than 6 inches tall and than 2 inches. less than 6 inches apaR within a 400-square foot area. Modular Grid Build-up of sediment mildly contaminated with Removal of sediment and disposal Pavement petroleum hydrocarbons. in keeping with Health Department recommendations for mildly contaminated soils or catch basin sediments. Shoulders and Erosion Damage Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and ' Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and Brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches in hinder maintenance access. height or cleared in such a way as to allow maintenance access. , - 1/24/2005 2005 Surface Water Design Manual—Appendix A A-10 ��i�i�i�.vi>>� n n�;�i�.i��:n��;�rv��i izi�� iit��n�ii�vi�tir��izi�i.�� vii;��i . c��mvi��;w��i�. ;�r.u ��1i��:��i.ii�ii�� NO. 16—WETPOND Maintenance Defect or Problem Condition When Maintenance is Needed Recommended Maintenance to Component Correct Problem Pond Area Water Level First cell empty,doesn't hold water. Line the first cell to maintain at least 4 feet of water. Although the second cell may drain,lhe first cell must remain full to control turbulence of the incoming flow and reduce sediment resuspension. Defective Vegetation Vegetation such as grass and weeds need to be Vegetation should be mowed to 4 to mowed when it starts to impede aesthetics of 5 inches in height. Trees and pond.Mowing is generally required when height bushes should be removed where exceeds 18 inches.Mowed vegetation should be they are interfering with pond removed from areas where it could enter the maintenance activities;that is, at the pond,either when the pond level rises,or by inlet, outlet and near engineered rainfall runoff. structures. Algae Mats When algae mats develop over more than 10% Algae mats that cover more than of the water surface,they should be removed. 10%of the surface of any cell Also remove mats in the late summer before fall should be removed. A rake or rains,especially in Sensitive Lake Protection mechanical device should be used Areas. Excessive algae mats interfere with to remove the algae. Removed dissoNed oxygen content in the water and pose a algae can be left to dry on the pond threat to downstream lakes if excess nutrients slope above the 100-year water are released. surface. Trash and Debris Accumulation that exceeds 1 cubic foot per 1000 Trash and debris removed from square foot of pond area. pond. Sediment Sediment accumulations in pond bottom that Removal of sediment from pond Accumulation exceeds the depth of sediment zone plus 6 bottom. inches, usually in the first cell. Oil Sheen on Water Prevalent and visible oil sheen. Remove oil from water by use of oil- absorbent pads or by vactor truck. Refer problem to locate source and correct. If chronic low levels of oil persist, plant wetland plants such as Juncus effusus (soft rush) which can uptake small concentrations of oil. Erosion Erosion of the pond's side slapes and/or Slopes should be stabilized by using scouring of the pond bottom,that exceeds 6 proper erosion control measures, inches, or where continued erosion is prevalent. and repair methods. Pond Dike/Berm Settlement Any part of these components that has settled 4 Dike/berm is repaired to inches or lower than the design elevation,or specifications. inspector determines dike/berm is unsound. Internal Berm Concentrated Flow Berm dividing cells should be level. Build up low areas of berm or lower high areas so that the berm surface is tevel and water flows even�y over the entire length of the berm from the first cell to the second. InIeUOutlet Pipe Sediment and Debris InIeUOutlet pipe clogged with sediment and/or No clogging or blockage in the inlet debris material. and outlet piping. Overflow Spillway Rock Missing Rock is missing and soil is exposed at top of Replace rocks to specifications. spillway or outside slope. 2005 Surface Water Design Manual—Appendi�n 1-241200� ��-13 Operation & Maintenance �OM� Manual v01 � . 0 Bioretention Systems � C=:::NTECH� ENGINEERED SOLUTIONS / ■ Q � erra Bioreten?ion Systerns Table of Contents Overview • Filterra'R General Desc� pt o� • FilterraC` Schematic • Basic Operat;ons • Des;gn Maintenance • Maintenance Overview » Why Maintain? » When to Maintain? • Exclusion of Services • Maintenance Visit Summary • Maintenance Tools, Safety Equipr„ent c�nd Supplies • Maintenance Vis�t Procedur= C=:::NTECH� ENGINEERED SOLUTIONS ..�::��.CortechES.�o�,,:�f I•e��a � 800 338-1 122 General Description The following general specifications describe the general operations and maintenance requirements for the Contech Engineered Solutions LLC stormwater bioretention filtration system, the Filterra`. The system utilizes physical, chemica) and biological mechanisms of a soil, plant and microbe complex to remove pollutants typically found in urban stormwater runoff. The treatment system is a fully equipped, pre-constructed drop-in place unit designed for applications in the urban landscape to treat contaminated runoff. BiQcettrtUon Pla»tiSoHrM�uabe Complex �""'"` Rernaves Pollutants,TSS, Phosphorus,Nitrogen.Racte+ia. � keavy Metals.Hydrocarbons,et� + � i , � ;� -►, --lt _ ,�,� =;,' E,, .� �� :' < •._ � Mew or Existiny ._ ��''``_ ' . .... __ 'rt _ .. � +�(+h. �� I�ii�•tr.� lic�r:ti�;.. �d1Cf1�S111. � `` # �a '" .3;ri�qher Eleveuon CurbCutor � Otfier Means of �`�: �p _ � � sF�.�ri Bypau ftow L{rsr _ - . QVP1��OV:RPItP( f .�]�._..� , 'a.':. �� L � - _.. . �.,t ' � � . - ._ ��Ydfl C�Ut �. ' - . , _ :-�,. ,..�-,s _.... �. .�E _ .�.�,- il� .�.- - . .� _: .�_ . _ _- a..._......--.-�.. _ -_ r�:�;�� - � 4 �`��v • _`_. , . " ; S �'F ..�.� -��t; � ` � . � . R �� ,- ��# '��` '' _ � , ` f� � �:,` — - .:...- � �' - f i �! . �� # � �. �� :, , , ; .. .. : , � Stor mwater flows through a specially designed filter media mixture contained in a landscaped concrete container. The mixture immobilizes pollutants which are then decomposed, volatilized and incorporated into the biomass of the Filterrc system's micro/macro fauna and flora. Stormwater runoff flows through the media and into an underdrain system at the bottom of the container, where the treated water is discharged. Higher flows bypass the FilterraF to a downstream inlet e� outfall. Maintenance is a simple, inexpensive and safe operation that does not require confined space access, pumping �� vacuum equipment or specialized tools. Properly trained landscape pe�;onnel can e{fective�y maintc n Fiite�rc� S+orr.��at� systems by following instructions in th�s manual. www.ContechES.com/filterra � 800-338-1122 � �as�e �►�er�rttc�r�s . ,. __. FilterraOO is a bioretention system in a concrete box. • Help reduce pollutant loads leaving yo� �,�o�-e, Contaminated stormwater runoff enters the filter box through the curb inlet spreading over the 3-inch layer of mulch on the Simple maintenance of the Filterra� is required to cor,t surface of the filter media. As the water passes through the effective pollutant remova) from stormwater runoff before mulch layer, most of the larger sediment particles and heavy discharge into downstream waters. This procedure will a :: metals are removed through sedimentation and chemical extend the longevity of the living biofilter system. The uni� .: : reactions with the organic material in the mulch. Water passes recycle and accumulate pollutants within the biomass, b�- through the soil media where the finer particles are removed is also subjected to other materials entering the throat. Th _ and other chemical reactions take place to immobilize and may indude trash, silt and leaves etc. which will be contai-��; capture pollutants in the soil media. The cleansed water within the void below the top grate and above the mulch passes into an underdrain and flows to a pipe system or layer. Too much silt may inhibit the Filterra'sOO flow rate, other appropriate discharge point. Once the pollutants are which is the reason for site stabilization before activation. in the soil, the bacteria begin to break down and metabolize Regular replacement of the mulch stops accumulation of such. the materials and the plants begin to uptake and metabolize sediment. the pollutants. Some pollutants such as heavy metals, which When to Maintoin? are chemically bound to organic particles in the mulch, are released over time as the organic matter decomposes to Contech indudes a 1-year maintenance p'lan �.•.itn eacn release the metals to the feeder roots of the plants and the system purchase. Annual included maintenance consists of a celis of the bacteria in the soil where they remain and are maximum of two (2) scheduled visits. Additional maintenance recycled. Other pollutants such as phosphorus are chemically may be necessary depending on sediment and trash loading bound to the soil particles and released slowly back to the (by Owner or at additional cost). The start of the maintenance plants and bacteria and used in their metabolic processes. plan begins when the system is adivated for full operation. Nitrogen goes through a very complex variety of biochemical Fuil operation is defined as the unit installed, curb and gutter processes where it can ultimately end up in the plant/bacteria and transitions in place and activation (by Supplier) when biomass, turned to nitrogen gas or dissolves back into the mulch and plant are added and temporary throat protection ' water column as nitrates depending on soil temperature, pH removed. and the availability of oxygen. The pollutants ultimately are Activation cannot be carried out until the site is fully stabilized retained in the mulch, soil and biomass with some passing out (full landscaping, grass cover, finaf paving and street sweeping of the system into the air or back into the water. completed). Maintenance visits are scheduled seasonally; the Design and Installation spring visit aims to clean up after winter loads including salts and sands while the fall visit helps the system by removing Each project presents different scopes for the use of excessive leaf litter. FilterroOO systems. To ensure the safe and specified function of the stormwater BMP, Contech reviews each application It has been found that in regions which receive between 30-Sd before supply. Information and help may be provided to inches of annual rainfall, (2) two visits are generally required; the design engineer during the planning process. Correct regions with less rainfall often only require (1) one visit per FilterraOO box sizing (by rainfall region) is essential to predict annum. Varying land uses can affect maintenance frequency; pollutant removal rates for a given area. The engineer shall e.g. some fast food restaurants require more frequent trash ' submit calculations for approval by the local jurisdiction. removal. Contributing drainage areas which are subject to new The contractor is responsible for the correct instaliation of development wherein the recommended erosion and sediment - Filterra units as shown in approved plans. A comprehensive control measures have not been implemented may require jinstallation manual is available at www.conteches.com. additional maintenance visits. Maintenanee Some sites may be subjected to extreme sediment or trash , loads, requiring more frequent maintenance visits. This is the Why Maintain? reason for detailed notes of maintenance actions per unit, helping the Supplier and Owner predict future maintenance All stormwater treatment systems require maintenance for frequencies, reflecting individual site conditions. effective operation. This necessity is often incorporated in ' your property's permitting process as a legally binding BMP Owners must promptly notify the (maintenance) Supplier of maintenance agreement. any damage to the plant(s), which constitute(s) an integr c! :art • Avoid legal challenges from your jurisdiction's of the bioretention technology. Owners should also au::�� other landscape or maintenance contractors to leave c'' maintenance enforcement program. i _. , � _� •� •_,r S� ��.�li�,� ��.e. r� �_��u'��r� ,'� fe ' z � ._ • Prolong the expected lifespan of your Filterra medic �' ;_� , =-c� =5.�� _. �, 80 �3��. 1 ' �2 Exclusion of Services It is the responsibility of the owner to provide adequate irrigation when necessary to the plant of the Filterrau system. Clean up due to major contamination such as oils, chemicals, toxic spills, etc. will result in additional costs and are not covered under the Supplier maintenance contract. Should a major contamination event occur the Owner must block off the outlet pipe of the FilterraOO (where the cleaned runoff drains to, such as drop inlet) and block off the throat of the FilterraOO. The Supplier should be informed immediately. Maintenance Visit Summary Each maintenance visit consists of the following simple tasks (detailed instructions below). 1. Inspection of FilterraOO and surrounding area 2. Removal of tree grate and erosion control stones 3. Removal of debris, trash and mulch 4. Mulch replacement S. Plant health evaluation and pruning or replacement as necessary b. Clean area around FilterraOO 7. Complete paperwork Maintenance Tools, Safety Equipment and Supplies Ideal tools include: camera, bucket, shovel, broom, pruners, hoe/rake, and tape measure. Appropriate Personal Protective Equipment (PPE) should be used in accordance with loca) or company procedures. This may include impervious gloves where the type of trash is unknown, high visibility clothing and barricades when working in close proximity to traffic and also safety hats and shoes. A T-Bar or crowbar should be used for moving the tree grates (up to 170 Ibs ea.). Most visits require minor trash removal and a full replacement of mulch. See below for actual number of bagged mulch that is required in each unit size. Mulch should be a double shredded, hardwood variety; do not use colored or dyed mulch. Some visits moy require additional FilterraOO engineered soil media available from the Supplier. � ' • " i = f • �• ' • i• • _ �• ��• 4 4 16 4 2 6 4 24 6 3 8 4 32 8 4 6 6 36 9 5 8 6 48 12 6 10 6 60 15 8 12 6 72 18 9 13 7 91 23 12 www.ContechES.com/filterra � 800-338-1122 I� -- -- Maintenance Visit Procedure Keep sufficient documentation of maintenance actions to predict loco-lo, _ specific maintenance frequencies and needs. An example Maintenancr R�pc�t ' is included in this man�al. 1. Inspection of Filterra0 and surrounding area " - " � - -�� - - • Record individua) unit before maintenance with photograph ;�� '�er�di. Record on Meinter,ance Repor' {see exaa�ple in this �ocument; •he : , �-'�� , �' following: ��; ° •� s, � �+ `��`� ` Record on Maintenance Repori the following: " � ��-�� . � Standing Water yes � no Damage to Box Structure yes � no �� I I�' � Oamage to Grate yes � no .�� Is Bypass Clear yes ( no If yes answered to any of these observations, record with close-up photograph (numbered). �, � � I �� '`� 2. Removal of tree grate and erosion control stones ' _ � �,#= � .R �'. , �; Remove cast iron grates for access mto Filterra� box. _ ��" �� • Di out silt if an and mulch and remove trash & forei n items. �"�� <. `�'1�� . � _ 9 � Y) 9 � � � �. �'r � � . . '�::� �"' Record on Maintenance Re ort the followin ��` p g� , �, � Silt/Clay yes � no �j' Cups/ Bags yes � no �_ Leaves yes � no -- # of Buckets Removed t 3. Removal of debris, trash and mulch • After remova) of mulch and debris, meas�re distance from the top of ��... � , the Filterra� engineered media soil to the bottom of the top slab. If this �`' � �` ��' distance is greater than 12", add FilterraOO media (not top soil or other) to '��`� �� recharge to a 9" distance E � `�� tr3 , . �$��. ��p ��. . Record on Maintenance Report the following: r_ � .a �` 7 Distance of Bottom of Top Slab (inches) # of Buckets of Media Added � , • �� ,�--�,. ....,.;.Co�,techES.co��,�-��!terrc 800-338-? 122 �.'�'`"`� ',. � ;�, f '��' � } 4. Mulch replacement 1. �-! �� `� ��,�"'' • Please see mulch specifications. , ; �s��„ a.. . . �.. �_ �.. : - _�� • Add double shredded mulch evenly ocross the entire unrf to a depth of 3". ., `� �'� �; r - • Ensure corred repositioning of erosion control stones by the Filterra0 inlet �;, � r '-�':�+.r. -:f �' to allow for entry of trash during a storm event. F� �;��' � -%'�` • Replace FilterraOO grates correctly using appropriate lifting or moving tools, f taking care not to damage the plant. � }� �_� . ,,.�.'o`�.. 5. Plant health evaluation and pruning or replacement `� `- � `� r � as necessary � .i '� • Exam�ne the plant's health and replace if dead. � • Prune as necessa to encoura e rowth in the correct directions 4 � rY 9 9 � � * � _ - �` Record on Maintenance Report the following: � r-1 �' " ,� 'R� � , �. .��-�' - � ' i� ; � Height above Grate (ft) �.. �°-� �' �` � .. �' `�` ' , Width at Widest Point (ft) ��. z, � ;:� a Health alive � dead � -'` - �. r �' * si"' Damage to Plant yes � no . �,�,i �� '� � � �' Plant Replaced yes � no � �,L f� �i ' ��y -� � ��' � .'7. �' . - .- - � k_+�:i". '�- � , T- , � 6. Clean area around Fiiterra0 ,�, � a� ;' �� • Clean area around unit and remove all refuse to be disposed of "�! {. - appropr�ately. . a . �f:f@:.t . -. •t�" '�'i�G`'� `i 'a" . � . • 'Y:t� J �s�+p�, `�: :;��-� � -- � - - : .... ��. � �; � � �'�"•M-� � 7. Com lete a erwork �`�}�- P P P � ,« �4_'��. p� =. � • Deliver Maintenance Report and photographs to appropriate location ��,�, �.�- (normally Contech during maintenance contract period). �'�--� ' • Some jurisdictions may require submission of maintenance reports in �`.� accordance with approvals. It is the responsibility of the Owner to comply � S v,-ith locol regulations. --��y,� � � r�.. � `�� '� � www.ContechES.com/filterra � 800-338-1122 Maintenance Checklist � . .. - - .. a • • . . - • • • . e • y • • ' ' �iliE'1 �f�IJUI.�. :JC ilcC CiP �� Excessive Accumulated sediments obstructions allowing free Sediments and/or trash � Inlet sediment or trash or trash impair free flow distributed flow of water should be removed. accumulation. of water into Filterra. into Filterra. Trash and debris should� Trash and be removed and mulch Mulch Cover floatable debris Excessive trash and/or Minima) trash or other cover raked level. Ensure accumulation. debris accumulation. debris on mulch cover. bark n�gget mulch is not used. "Ponding" in unit could "Ponding" of be indicative of clogging Stormwater should drain Recommend contact Mulch Cover water on mulch due to excessive fine freely and evenly through manufacturer and replace mulch as a cover. sediment accum�lation mulch cover. � or spill of petroleum oils. minimum. , Soil/mulch too wet, Plants not evidence of spill. p�ants should be healthy Contact manufacturer Vegetation growing or in Incorrect plant selection. and pest free. for advice. poor condition. Pest infestation. , Vandalism to plants. �I Plants should be Trim/prune plants in I Plant growth appropriate to the accordance with typical � Vegetation I excessive. species and location of landscaping and safety , Filterra. needs. � Cracks wider than 1/2 ' Structure has inch or evidence of soil Structure visible cracks. Particles entering the Vault should be repaired. structure through the cracks. 11�_;�.,,_„n ct ; ,r.,,��;: �,,��r,,,�d t - :,.,-i,oi'b �� C=:::NTECH� ENGINEERED SOLUTIONS �;�,� , :� � ,�, F . ,,, � �, -� ,, ,_��_ -- _ �.. � �._ '=:�,ES _� �� _. 8C�(�� ?1q , 1'7�